Author: "SPINtronique et TEchnologie des Composants (SPINTEC)" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"SPINtronique et TEchnologie des Composants (SPINTEC)"' showing total 749 results

Start Over Author "SPINtronique et TEchnologie des Composants (SPINTEC)"

749 results on '"SPINtronique et TEchnologie des Composants (SPINTEC)"'

1. Focused Kerr measurements on patterned arrays of exchange biased square dots

Author: SPINtronique et technologie des composants (SPINTEC - UMR 8191) ; CNRS - CEA - CEA, CROCUS Technology ; CROCUS Technology, MNM ; Institut Néel (NEEL) ; Université Grenoble Alpes - CNRS - Université Grenoble Alpes - CNRS, European Project : 246942, ERC, ERC-2009-AdG, HYMAGINE(2010), Vinai, G., Moritz, J., Gaudin, G., Vogel, Jan, Prejbeanu, I.L., Dieny, B., SPINtronique et technologie des composants (SPINTEC - UMR 8191) ; CNRS - CEA - CEA, CROCUS Technology ; CROCUS Technology, MNM ; Institut Néel (NEEL) ; Université Grenoble Alpes - CNRS - Université Grenoble Alpes - CNRS, European Project : 246942, ERC, ERC-2009-AdG, HYMAGINE(2010), Vinai, G., Moritz, J., Gaudin, G., Vogel, Jan, Prejbeanu, I.L., and Dieny, B.
Abstract: International audience, Microstructural effects on the antiferromagnetic layer were investigated on IrMn/Co exchange biased square dots. IrMn grain size and distributions were tuned by changing Cu buffer layer or IrMn thicknesses. Lateral dimensions from 200 to 50nm were varied. Exchange bias (Hex) variability was analysed through focused Kerr measurements on small groups of dots. Patterned samples presented average exchange bias values following the trends and values of full sheet samples. Concerning the dot to dot behaviour, it resulted that IrMn microstructure variations have minor effects on Hex variability, because no particular trend is observed as a function of grain size and distribution. The variability is attributed to geometry variation and Co intrinsic variability.

2. Spintronic Memristor-Based Binarized Ensemble Convolutional Neural Network Architectures

Author: Ghislain Takam Tchendjou, Kamal Danouchi, Guillaume Prenat, Lorena Anghel, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019)
Subjects: [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Electrical and Electronic Engineering, Computer Graphics and Computer-Aided Design, Software
Abstract: International audience
Published: 2023
Full Text: View/download PDF

3. Band-bending induced by charged defects and edges of atomically thin transition metal dichalcogenide films

Author: Pierre Mallet, Minh Tuan Dau, Jean-Yves Veuillen, K. Nogajewski, Matthieu Jamet, T. Le Quang, Marek Potemski, QNES - Nano-Electronique Quantique et Spectroscopie, Institut Néel ( NEEL ), Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes [Saint Martin d'Hères]-Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes [Saint Martin d'Hères], Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes [Saint Martin d'Hères], Laboratoire national des champs magnétiques intenses - Grenoble ( LNCMI ), Centre National de la Recherche Scientifique ( CNRS ), SPINtronique et technologie des composants ( SPINTEC - UMR 8191 ), Institut Nanosciences et Cryogénie ( INAC ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Grenoble Alpes ( UGA ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Grenoble Alpes ( UGA ) -Centre National de la Recherche Scientifique ( CNRS ), ANR-14-CE26-0017,MoS2ValleyControl,Propriétés optiques et de transport dans des mono-couches de MoS2 et discpositifs associés ( 2014 ), European Project : 604391,EC:FP7:ICT,FP7-ICT-2013-FET-F,GRAPHENE ( 2013 ), European Project : 320590,EC:FP7:ERC,ERC-2012-ADG_20120216,MOMB ( 2013 ), Nano-Electronique Quantique et Spectroscopie (QuNES), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G ), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-14-CE26-0017,MoS2ValleyControl,Propriétés optiques et de transport dans des mono-couches de MoS2 et discpositifs associés(2014), European Project: 604391,EC:FP7:ICT,FP7-ICT-2013-FET-F,GRAPHENE(2013), European Project: 320590,EC:FP7:ERC,ERC-2012-ADG_20120216,MOMB(2013), Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Materials science, [ PHYS.COND.CM-MS ] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], charge screening, 02 engineering and technology, Dielectric, 01 natural sciences, law.invention, charged defect, law, Electric field, 0103 physical sciences, Monolayer, General Materials Science, 010306 general physics, Condensed matter physics, Graphene, Mechanical Engineering, scanning tunneling microscopy/spectroscopy, graphene, General Chemistry, transition metal dichalcogenide, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electrostatics, film edges, Crystallographic defect, Band bending, Mechanics of Materials, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], van der Waals heterostructures, Scanning tunneling microscope, 0210 nano-technology
Abstract: International audience; We report scanning tunneling microscopy/spectroscopy (STM/STS) investigations of the bandbendingin the vicinity of charged point defects and edges of monolayer MoSe$_2$ and mono- andtrilayer WSe$_2$ films deposited on graphitized silicon carbide substrates. By tracing the spatialevolution of the structures of the STS spectra, we evaluate the magnitude and the extent of theband-bending to be equal to few hundreds milielectronvolts and several nanometres, respectively.With the aid of a simple electrostatic model, we show that the spatial variation of the Coulombpotential close to the film edges can be well reproduced by taking into account the metallic screeningby graphene. Additionally, the analysis of our data for trilayer WSe$_2$ provides reasonable estimationsof its dielectric constant ($\epsilon_{WSe}$$_2$ = 20) and of the magnitude of the charge trapped at the defect site(Q = $+e$).
Published: 2018
Full Text: View/download PDF

4. Conditioning Circuits for Nanoscale Perpendicular Spin Transfer Torque Magnetic Tunnel Junctions as Magnetic Sensors

Author: Hugo Nicolas, Ricardo C. Sousa, Ariam Mora-Hernández, Ioan-Lucian Prejbeanu, Luc Hebrard, Jean-Baptiste Kammerer, Joris Pascal, University of Applied Sciences Northwestern Switzerland (FHNW), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and Université de Strasbourg (UNISTRA)
Subjects: [SPI]Engineering Sciences [physics], Spin transfer torque, STT-MTJ, STT-MRAM, Nanometer scale, Magnetic sensor, Magnetic tunnel junction, Electrical and Electronic Engineering, Instrumentation
Abstract: International audience
Published: 2023
Full Text: View/download PDF

5. Electrical modeling of spin-torque diodes used as radio frequency detectors: a step-by-step methodology for parameter extraction

Author: Imadeddine Bendjeddou, Mafalda Jotta Garcia, Ahmed Sidi el Valli, Artem Litvinenko, Vincent Cros, Ursula Ebels, Alex Jenkins, Ricardo Ferreira, Roberta Dutra, Dominique Morche, Emmanuel Pistono, Sylvain Bourdel, Yannis Le Guennec, Florence Podevin, Reliable RF and Mixed-signal Systems (TIMA-RMS), Techniques de l'Informatique et de la Microélectronique pour l'Architecture des systèmes intégrés (TIMA), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), GIPSA Pôle Géométrie, Apprentissage, Information et Algorithmes (GIPSA-GAIA), Grenoble Images Parole Signal Automatique (GIPSA-lab), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), International Iberian Nanotechnology Laboratory (INL), and ANR-18-CE24-0012,SPINNET,La spintronique microondes pour les réseaux de capteurs sans fils(2018)
Subjects: parameter extraction, Radiation, PACS 8542, electrical modeling, RF-to-dc conversion, Electrical and Electronic Engineering, spin-torque diodes (STDs), [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Condensed Matter Physics, radio frequency (RF) detector
Abstract: International audience; In this article here below, we present an electrical model for nanoscale spintronic radio frequency (RF) detectors called spin-torque diodes (STDs). A complete methodology for model parameter extraction is proposed. An equivalent electrical circuit for STD is derived and includes a modeling of the device resistance nonlinearity together with the STD effect. A detailed step-by-step methodology is presented to extract the model parameters using conventional dc measurements, RF scattering parameters (S -parameters), continuous wave (CW), and power characterizations. After parameter extraction, a comparison with measurements of a single STD successfully validates the model. Finally, the proposed STD electrical model is used to anticipate the behavior of a two-STD-based RF detector architecture. Simulation results highlight the interest of the proposed modeling approach to investigate suitable RF detector architectures to enhance RF-to-dc conversion efficiency for single or multiband RF detection.
Published: 2023
Full Text: View/download PDF

6. Leveraging Sparsity with Spiking Recurrent Neural Networks for Energy-Efficient Keyword Spotting

Author: Dampfhoffer, Manon, Mesquida, Thomas, Hardy, Emmanuel, Valentian, Alexandre, Anghel, Lorena, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Département Systèmes et Circuits Intégrés Numériques (DSCIN), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'électronique et des technologies de l'Information [Sfax] (LETI), and École Nationale d'Ingénieurs de Sfax | National School of Engineers of Sfax (ENIS)
Subjects: Spiking neural networks, speech commands, energy-efficiency, sparsity, [INFO.INFO-SD]Computer Science [cs]/Sound [cs.SD], keyword spotting, [INFO.INFO-NE]Computer Science [cs]/Neural and Evolutionary Computing [cs.NE], [INFO.INFO-CL]Computer Science [cs]/Computation and Language [cs.CL]
Abstract: International audience; Bio-inspired Spiking Neural Networks (SNNs) are promising candidates to replace standard Artificial Neural Networks (ANNs) for energy-efficient keyword spotting (KWS) systems. In this work, we compare the trade-off between accuracy and energy-efficiency of a gated recurrent SNN (Spik-GRU) with a standard Gated Recurrent Unit (GRU) on the Google Speech Command Dataset (GSCD) v2. We show that, by taking advantage of the sparse spiking activity of the SNN, both accuracy and energy-efficiency can be increased. Lever-aging data sparsity by using spiking inputs, such as those produced by spiking audio feature extractors or dynamic sensors, can further improve energy-efficiency. We demonstrate state-of-the-art results for SNNs on GSCD v2 with up to 95.9% accuracy. Moreover, SpikGRU can achieve similar accuracy than GRU while reducing the number of operations by up to 82%.
Published: 2023
Full Text: View/download PDF

7. MOZART+: Masking Outputs With Zeros for Improved Architectural Robustness and Testing of DNN Accelerators

Author: Stephane Burel, Adrian Evans, Lorena Anghel, Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: [INFO.INFO-ES]Computer Science [cs]/Embedded Systems, Electrical and Electronic Engineering, Safety, Risk, Reliability and Quality, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], Electronic, Optical and Magnetic Materials
Abstract: International audience; Deep Neural Networks (DNNs) are increasingly used in safety critical autonomous systems. We present MOZART+, a DNN accelerator architecture which provides fault detection and fault tolerance. MOZART+ is a systolic architecture based on the Output Stationary (OS) data-flow, as it is a data-flow that inherently limits fault propagation. In addition, MOZART+ achieves fault detection with on-line functional testing of the Processing Elements (PEs). Faulty PEs are swiftly taken off-line with minimal classification impact. We show how to handle the case of layers with a small number of neurons. The implementation of our approach on Squeezenet results in a loss of accuracy of less than 3% in the presence of a single faulty PE, compared to 15-33% without mitigation. The area overhead for the test logic does not exceed 8%. Dropout during training further improves fault tolerance, without a priori knowledge of the faults. We present a detailed fault-injection study on multiple systolic architectures, considering different fault-models and comparing different measures of accuracy.
Published: 2022
Full Text: View/download PDF

8. Observation of non-Hermitian topology in a multi-terminal quantum Hall device

Author: Ochkan, Kyrylo, Chaturvedi, Raghav, Könye, Viktor, Veyrat, Louis, Giraud, Romain, Mailly, Dominique, Cavanna, Antonella, Gennser, Ulf, Hankiewicz, Ewelina M., Büchner, Bernd, Brink, Jeroen van den, Dufouleur, Joseph, Fulga, Ion Cosma, Leibniz Institute for Solid State and Materials Research (IFW Dresden), Leibniz Association, Dresden-Würzburg Center of Excellence on Complexity and Topology in Quantum Matter (ct.qmat), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institute for Theoretical Physics and Astrophysics [Würzburg], Julius-Maximilians-Universität Würzburg (JMU), Department of Physics [TU Dresden], and Technische Universität Dresden = Dresden University of Technology (TU Dresden)
Subjects: effet Hall quantique, topology, Condensed Matter - Mesoscale and Nanoscale Physics, circuits éléctroniques, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), FOS: Physical sciences, electronic circuits, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], quantum Hall effect, topologie
Abstract: Quantum devices characterized by non-Hermitian topology are predicted to show highly robust and potentially useful properties, but realizing them has remained a daunting experimental task. This is because non-Hermiticity is often associated with gain and loss, which would require precise tailoring to produce the signatures of nontrivial topology. Here, instead of gain/loss, we use the nonreciprocity of the quantum Hall edge states to directly observe non-Hermitian topology in a multi-terminal quantum Hall ring. Our transport measurements evidence a robust, non-Hermitian skin effect: currents and voltages show an exponential profile, which persists also across Hall plateau transitions away from the regime of maximum non-reciprocity. Our observation of non-Hermitian topology in a quantum device introduces a scalable experimental approach to construct and investigate generic non-Hermitian systems.; Les dispositifs quantiques caractérisés par une topologie non hermitienne ont des propriétés stables et potentiellement utiles pour les applications en métrologie ou pour la réalisation de simulateurs quantiques, mais leur réalisation expérimentale reste compliquée. En effet, la non-hermiticité est souvent associée à la dissipation avec l'environnement, ce qui nécessite une adaptation précise des dispositifs pour générer les signatures d'une topologie non triviale. Dans ce travail, au lieu des échanges d'énergie, nous utilisons la non-réciprocité des états de bord en régime d'effet Hall quantique pour observer directement la topologie non hermitienne d'un anneau quantique multi-terminal. Nos mesures de transport mettent en évidence un effet non hermitien dit de peau : les courants et les tensions montrent un profil exponentiel, qui persiste également hors des plateaux de Hall, et plus généralement en dehors du régime de non-réciprocité maximale. Notre observation de la topologie non hermitienne dans un dispositif quantique introduit une approche simple et adaptée à l'intégration en microélectronique pour construire et étudier des systèmes génériques non hermitiens, basés de façon générale sur l'utilisation de canaux de bords chiraux.
Published: 2023

9. The basics of electron transport in spintronics: textbook with lectures, exercises and solutions

Author: Vincent Baltz, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Abstract: International audience; Here is the ideal book to grasp the basic concepts of spin-dependent electron transport and to develop a deep physical understanding of the subject. A careful selection of key notions provides a concise and effective framework. Learning how to use these notions is successfully supported by ten extended exercises with complete solutions. Common terms and specialist jargon are clearly explained, and the way in which subtleties complicate phenomena, without altering their physical basis, is pedagogically addressed. The rigorous and harmonised system of notation and units adopted throughout the book allows the reader to navigate easily between concepts and to gain a broad view of the subject. Based on a series of lectures given to MSc and PhD students, this book will appeal to a wide range of readers, from students at the graduate level to researchers and engineers. The present extract contains the front cover, the foreword, the preface, and the table of contents.
Published: 2023

10. On Using Cell-Aware Methodology for SRAM Bit Cell Testing

Author: Xhafa, Xh., Ladhar, A., Faehn, E., Anghel, L., Di Pendina, G., Girard, P., Virazel, A., Laboratoire d'Informatique de Robotique et de Microélectronique de Montpellier (LIRMM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), ST Microélectronics, ST Microélectronic, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: [SPI]Engineering Sciences [physics]
Published: 2023
Full Text: View/download PDF

11. Atomic-layer controlled THz Spintronic emission from Epitaxially grown Two dimensional PtSe$_2$/ferromagnet heterostructures

Author: Abdukayumov, K., Mičica, M., Ibrahim, F., Vergnaud, C., Marty, A., Veuillen, J. -Y., Mallet, P., de Moraes, I. Gomes, Dosenovic, D., Wright, A., Tignon, J., Mangeney, J., Ouerghi, A., Renard, V., Mesple, F., Bonell, F., Okuno, H., Chshiev, M., George, J. -M., Jaffrès, H., Dhillon, S., Jamet, M., SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), ANR-18-CE24-0007,MAGICVALLEY,Polarisation de vallée induite par couplage d'échange magnétique dans les matériaux 2D à grande échelle(2018), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), ANR-21-ESRE-0025,2D-MAG,Two-dimensional magnetic materials(2021), European Project: 238700,EC:FP7:PEOPLE,FP7-PEOPLE-ITN-2008,NANOPOLY(2009), and European Project: 881603,H2020,H2020-SGA-FET-GRAPHENE-2019, GrapheneCore3(2020)
Subjects: [PHYS]Physics [physics], Condensed Matter - Materials Science, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences
Abstract: Terahertz (THz) Spintronic emitters based on ferromagnetic/metal junctions have become an important technology for the THz range, offering powerful and ultra-large spectral bandwidths. These developments have driven recent investigations of two-dimensional (2D) materials for new THz spintronic concepts. 2D materials, such as transition metal dichalcogenides (TMDs), are ideal platforms for SCC as they possess strong spin-orbit coupling (SOC) and reduced crystal symmetries. Moreover, SCC and the resulting THz emission can be tuned with the number of layers, electric field or strain. Here, epitaxially grown 1T-PtSe$_2$ and sputtered Ferromagnet (FM) heterostructures are presented as a novel THz emitter where the 1T crystal symmetry and strong SOC favor SCC. High quality of as-grown PtSe$_2$ layers is demonstrated and further FM deposition leaves the PtSe$_2$ unaffected, as evidenced with extensive characterization. Through this atomic growth control, the unique thickness dependent electronic structure of PtSe$_2$ allows the control of the THz emission by SCC. Indeed, we demonstrate the transition from the inverse Rashba-Edelstein effect in one monolayer to the inverse spin Hall effect in multilayers. This band structure flexibility makes PtSe$_2$ an ideal candidate as a THz spintronic 2D material and to explore the underlying mechanisms and engineering of the SCC for THz emission., 26 pages, 6 figures
Published: 2023

12. Field-Free Spin-Orbit Torque driven Switching of Perpendicular Magnetic Tunnel Junction through Bending Current

Author: Kateel, Vaishnavi, Krizakova, Viola, Rao, Siddharth, Cai, Kaiming, Gupta, Mohit, Monteiro, Maxwel Gama, Yasin, Farrukh, Sorée, Bart, De Boeck, Johan, Couet, Sébastien, Gambardella, Pietro, Kar, Gouri Sankar, Garello, Kevin, IMEC (IMEC), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Department of Electrical Engineering - K.U.Leuven (ESAT/SCD-COSIC), Department of Materials [ETH Zürich] (D-MATL), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Departement Elektrotechniek - ESAT [leuven], SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: [PHYS]Physics [physics], memories, spintronics, field-free switching, spin-orbit torques, magnetic tunnel junction, MRAM, Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), FOS: Physical sciences, Applied Physics (physics.app-ph), Physics - Applied Physics
Abstract: Current-induced spin-orbit torques (SOTs) enablefast andefficient manipulation of the magnetic state of magnetic tunnel junctions(MTJs), making them attractive for memory, in-memory computing, andlogic applications. However, the requirement of the external magneticfield to achieve deterministic switching in perpendicularly magnetizedSOT-MTJs limits its implementation for practical applications. Here,we introduce a field-free switching (FFS) solution for the SOT-MTJdevice by shaping the SOT channel to create a "bend"in the SOT current. The resulting bend in the charge current createsa spatially nonuniform spin current, which translates into inhomogeneousSOT on an adjacent magnetic free layer enabling deterministic switching.We demonstrate FFS experimentally on scaled SOT-MTJs at nanosecondtime scales. This proposed scheme is scalable, material-agnostic,and readily compatible with wafer-scale manufacturing, thus creatinga pathway for developing purely current-driven SOT systems., Nano Letters, 23 (12), ISSN:1530-6984, ISSN:1530-6992
Published: 2023
Full Text: View/download PDF

13. Non-volatile electric control of spin-orbit torques in an oxide two-dimensional electron gas

Author: Cécile Grezes, Aurélie Kandazoglou, Maxen Cosset-Cheneau, Luis M. Vicente Arche, Paul Noël, Paolo Sgarro, Stephane Auffret, Kevin Garello, Manuel Bibes, Laurent Vila, Jean-Philippe Attané, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), and THALES [France]-Centre National de la Recherche Scientifique (CNRS)
Subjects: Condensed Matter - Materials Science, Condensed Matter::Materials Science, Multidisciplinary, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, General Physics and Astronomy, General Chemistry, General Biochemistry, Genetics and Molecular Biology
Abstract: Spin-orbit torques (SOTs) have opened a novel way to manipulate the magnetization using in-plane current, with a great potential for the development of fast and low power information technologies. It has been recently shown that two-dimensional electron gases (2DEGs) appearing at oxide interfaces provide a highly efficient spin-to-charge current interconversion. The ability to manipulate 2DEGs using gate voltages could offer a degree of freedom lacking in the classical ferromagnetic/spin Hall effect bilayers for spin-orbitronics, in which the sign and amplitude of SOTs at a given current are fixed by the stack structure. Here, we report the non-volatile electric-field control of SOTs in an oxide-based Rashba-Edelstein 2DEG. We demonstrate that the 2DEG is controlled using a back-gate electric-field, providing two remanent and switchable states, with a large resistance contrast of 1064%. The SOTs can then be controlled electrically in a non-volatile way, both in amplitude and in sign. This achievement in a 2DEG-CoFeB/MgO heterostructures with large perpendicular magnetization further validates the compatibility of oxide 2DEGs for magnetic tunnel junction integration, paving the way to the advent of electrically reconfigurable SOT MRAMS circuits, SOT oscillators, skyrmion and domain-wall-based devices, and magnonic circuits., Nature Communications, 14 (1), ISSN:2041-1723
Published: 2023
Full Text: View/download PDF

14. From Early Theories of Dzyaloshinskii-Moriya Interactions in Metallic Systems to Today's Novel Roads

Author: Albert Fert, Mairbek Chshiev, André Thiaville, Hongxin Yang, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Laboratoire de Physique des Solides (LPS), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), National Laboratory of Solid State Microstructures [Nanjing University] (LSSMS), Nanjing University (NJU), and European Project: 881603,H2020,H2020-SGA-FET-GRAPHENE-2019, GrapheneCore3(2020)
Subjects: Condensed Matter - Materials Science, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Physics and Astronomy, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Abstract: Since the early 1960's, the discovery of Dzyaloshinskii-Moriya interaction (DMI) helped to explain the physical mechanisms behind certain magnetic phenomena, such as net moment in antiferromagnets, or enhanced anisotropy field from heavy metals impurity in dilute Cu:Mn alloy. Since the researchers unveil the key role that DMI plays in stabilizing chiral Neel type magnetic domain wall and magnetic skyrmions, the studies on DMI have received growing interest. Governed by spin-orbit coupling (SOC) and various types of inversion symmetry breaking (ISB) in magnetic systems, DMI drives the forming of distinct morphologies of magnetic skyrmions. Our aim is to briefly introduce the research history of DMI and its significance in the field of modern spintronics., Published in J. Phys. Soc. Jpn
Published: 2023
Full Text: View/download PDF

15. Epitaxial van der Waals heterostructures of Cr 2 Te 3 on two-dimensional materials

Author: Guillet, Quentin, Vojáček, Libor, Dosenovic, Djordje, Ibrahim, Fatima, Boukari, Hervé, Li, Jing, Choueikani, Fadi, Ohresser, Philippe, Ouerghi, Abdelkarim, Mesple, Florie, Renard, Vincent, Jacquot, Jean-François, Jalabert, Denis, Okuno, Hanako, Chshiev, Mairbek, Vergnaud, Céline, Bonell, Frédéric, Marty, Alain, Jamet, Matthieu, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Nanophysique et Semiconducteurs (NEEL - NPSC), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Transport Electronique Quantique et Supraconductivité (LaTEQS), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Microbiologie Environnementale et Moléculaire (MEM), Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB) (BIAM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Institut Universitaire de France (IUF), and Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.)
Subjects: [PHYS]Physics [physics], [SPI]Engineering Sciences [physics]
Abstract: International audience; Abstract The recent discovery of superconductivity in paramagnetic UTe 2 turns spotlight on a serious candidate for spin-triplet state. To draw a complete picture of the superconducting state in UTe 2 precise knowledge of the electronic properties of the 5 f states of Uranium is missing. We report on x-ray absorption and magnetic circular dichroism experiments performed at the U M 4,5 edges at 2.7 K. At ambient pressure the 5 f electron count is found to be in-between 2.6 and 2.8. Partial delocalization of the 5 f electrons is further confirmed by the reduced value of the U orbital to spin magnetic moment ratio. The 5 f count is reduced by as large as 7 percent at the transition to a magnetically ordered state at P c ≈ 1.5 GPa. At pressures above 4 GPa, the 5 f count increases back towards U 3+ in the tetragonal phase. The observed “valence instabilities” and their interplay with magnetism seem to be important ingredients to understand the electronic structure in UTe 2 in different phases.
Published: 2023
Full Text: View/download PDF

16. Embedded Tutorial: Hardware design and Reliability Mitigation of Binary Bayesian ReasoningSpeakers: Lorena Anghel (Grenoble INP) and Mehdi Tahoori (KIT)

Author: Anghel, Lorena, Tahoori, Mehdi, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and IEEE
Subjects: [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics
Abstract: International audience
Published: 2023

17. SpinDrop: Dropout-Based Bayesian Binary Neural Networks With Spintronic Implementation

Author: Soyed Tuhin Ahmed, Kamal Danouchi, Christopher Münch, Guillaume Prenat, Lorena Anghel, Mehdi B. Tahoori, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Karlsruhe Institute of Technology (KIT), and ANR-21-FAI1-0008,NEUSPIN,Conception d'un système intégré sur puce neuromorphique basé sur la spintronique à très faible consommation(2021)
Subjects: Bayesian neural network, Monte carlo dropout, Binary neural network, Spintronics, Electrical and Electronic Engineering, Binary bayesian neural network, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], [SPI.TRON]Engineering Sciences [physics]/Electronics
Abstract: Neural Networks (NNs) provide an effective solution in numerous application domains, including autonomous driving and medical applications. Nevertheless, NN predictions can be incorrect if the input sample is outside of the training distribution or contaminated by noise. Consequently, quantifying the uncertainty of the NN prediction allows the system to make more insightful decisions by avoiding blind predictions. Therefore, uncertainty quantification is crucial for a variety of applications, including safety-critical applications. Bayesian NN (BayNN) using Dropout-based approximation provides systematic approach for estimating uncertainty of predictions. Despite such merit, BayNNs are not suitable for implementation in a embedded device or able to meet high-performance demands for certain applications. Computation in-memory (CiM) architecture with emerging non-volatile memories (NVMs) are a great candidate for high performance and low power acceleration BayNNs in hardware. Among NVMs, Magnetic Tunnel Junction (MTJ) offer many benefits, but they also suffer from various non-idealities and limited bit-level resolution. As a result, binarizing BayNNs is an attractive option that can directly implement BayNN into a CiM architecture and able to achieve benefits of both CiM architecture and BayNNs at the same time. Conventional in- memory hardware implementations emphasize conventional NNs, which can only make predictions, does not account for both device and input uncertainty, thus, reducing both reliability and performance. In this paper, we propose for the first time Binary Bayesian NNs (BinBayNN) with an end to end approach (from algorithmic level to device level) for their implementation. Our approach takes the inherent stochastic properties of MTJs as a feature to implement Dropout-based Bayesian Neural Networks. We provide an extensive evaluation of our approach from the device level up to the algorithmic level on various benchmark datasets.
Published: 2023
Full Text: View/download PDF

18. Recent developments in the manipulation of magnetic domain walls in CoFeB–MgO wires for applications to high-density nonvolatile memories

Author: Pham , Van Tuong, Marty , Williams, Marty , Matthieu, Marty , Jean-Philippe, Zahnd , Gilles, Pham , T., Marty , Alain, Laczkowski , L, Savero Torres , T, Beigne , C., Vergnaud , C., Jamet , M., Attané , A, Ravelosona , D., Diez , L. Herrera, Zhao , W., Kläui , M., Ockert , B., Mantovan , R., Lamperti , A., Baldi , L., Jacques , V., Vila , Laurent, Cowburn , R., SPINtronique et TEchnologie des Composants ( SPINTEC ), Institut Nanosciences et Cryogénie ( INAC ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Grenoble Alpes ( UGA ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Grenoble Alpes ( UGA ) -Centre National de la Recherche Scientifique ( CNRS ), SC2G - Semi-conducteurs à large bande interdite, Institut Néel ( NEEL ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés ( LISBP ), Institut National de la Recherche Agronomique ( INRA ) -Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Institut d'électronique fondamentale ( IEF ), Université Paris-Sud - Paris 11 ( UP11 ) -Centre National de la Recherche Scientifique ( CNRS ), Systèmes interfaciaux à l'echelle nanometrique ( SIEN ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -ESPCI ParisTech-Centre National de la Recherche Scientifique ( CNRS ), Institut für Physik [Mainz], Johannes Gutenberg - Universität Mainz ( JGU ), Laboratoire de Physique des Solides ( LPS ), Institut d'électronique fondamentale (IEF), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Johannes Gutenberg - Universität Mainz (JGU), Singulus technology AG, Laboratorio MDM (IMM-CNR), Consiglio Nazionale delle Ricerche [Roma] (CNR), Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), University of Cambridge [UK] (CAM), Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)
Subjects: Materials science, Spintronics, Magnetic domain, Condensed matter physics, business.industry, [ PHYS.COND.CM-MS ] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 02 engineering and technology, magnetic domain walls, magnetic anisotropy, mass storage, 021001 nanoscience & nanotechnology, 01 natural sciences, Engineering physics, Magnetic field, Domain wall (magnetism), Semiconductor, CMOS, Electric field, 0103 physical sciences, Computer data storage, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, 0210 nano-technology, business, ComputingMilieux_MISCELLANEOUS, [ PHYS.COND ] Physics [physics]/Condensed Matter [cond-mat]
Abstract: The recent discovery that magnetic domain walls can be moved under a small current without any magnetic field opens a perspective for a paradigm shift in mass storage design. However, several fundamental questions must be answered before the technology can be considered feasible. This review covers the current understanding of domain wall (DW) propagation in CoFeB–MgO structures with perpendicular magnetic anisotropy. These films exhibit a very low density of pinning centers and can be integrated in Magnetic Tunnel Junctions, making them very promising for manipulating multiple domain walls in ultra-high-density spintronic devices. Several important issues are addressed: the physics of magnetic field, current and electric field driven domain wall motion, the characterization of the pinning potential on the nanoscale, the demonstration of artificial storing pinning sites, and the evaluation of domain wall propagation for logic and memory design integrated into complementary metal-oxide semiconductor (CMOS) technology.
Published: 2015
Full Text: View/download PDF

19. Quantitative Visualization of Thermally Enhanced Perpendicular Shape Anisotropy STT-MRAM Nanopillars

Author: Trevor P. Almeida, Steven Lequeux, Alvaro Palomino, Ricardo C. Sousa, Olivier Fruchart, Ioan-Lucian Prejbeanu, Bernard Dieny, Aurélien Masseboeuf, David Cooper, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and European Project: 669204,H2020,ERC-2014-ADG,MAGICAL(2015)
Subjects: thermomagnetic stability, nanomagnetism, Mechanical Engineering, Perpendicular shape anisotropy STT MRAM, off-axis electron holography, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, Bioengineering, General Chemistry, Condensed Matter Physics
Abstract: International audience; Perpendicular shape anisotropy (PSA) offers a practical solution to downscale spin-transfer torque magnetoresistive random-access memory (STT-MRAM) beyond the sub-20 nm technology node while retaining thermal stability. However, our understanding of the thermomagnetic behavior of PSA-STT-MRAM is often indirect, relying on magnetoresistance measurements and micromagnetic modeling. Here, the magnetism of a NiFe PSA-STT-MRAM nanopillar is investigated using off-axis electron holography, providing spatially resolved magnetic information as a function of temperature. Magnetic induction maps reveal the micromagnetic configuration of the NiFe storage layer (∼60 nm high, ≤20 nm diameter), confirming the PSA induced by its 3:1 aspect ratio. In situ heating demonstrates that the PSA of the storage layer is maintained up to at least 250 °C, and direct quantitative measurements reveal a moderate decrease of magnetic induction. Hence, this study shows explicitly that PSA provides significant stability in STT-MRAM applications that require reliable performance over a range of operating temperatures.
Published: 2022
Full Text: View/download PDF

20. The Magnetic Genome of Two-Dimensional van der Waals Materials

Author: Qing Hua Wang, Amilcar Bedoya-Pinto, Mark Blei, Avalon H. Dismukes, Assaf Hamo, Sarah Jenkins, Maciej Koperski, Yu Liu, Qi-Chao Sun, Evan J. Telford, Hyun Ho Kim, Mathias Augustin, Uri Vool, Jia-Xin Yin, Lu Hua Li, Alexey Falin, Cory R. Dean, Fèlix Casanova, Richard F. L. Evans, Mairbek Chshiev, Artem Mishchenko, Cedomir Petrovic, Rui He, Liuyan Zhao, Adam W. Tsen, Brian D. Gerardot, Mauro Brotons-Gisbert, Zurab Guguchia, Xavier Roy, Sefaattin Tongay, Ziwei Wang, M. Zahid Hasan, Joerg Wrachtrup, Amir Yacoby, Albert Fert, Stuart Parkin, Kostya S. Novoselov, Pengcheng Dai, Luis Balicas, Elton J. G. Santos, Arizona State University [Tempe] (ASU), Max Planck Institute of Microstructure Physics, Instituto de Ciencia Molecular (ICMol), Universitat de València (UV), Columbia University [New York], Department of Physics [Harvard University], Harvard University, Universität Duisburg-Essen = University of Duisburg-Essen [Essen], National University of Singapore (NUS), Condensed Matter Physics and Materials Sciences Department, Brookhaven National Laboratory [Upton, NY] (BNL), UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY)-U.S. Department of Energy [Washington] (DOE)-UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY)-U.S. Department of Energy [Washington] (DOE), Los Alamos National Laboratory (LANL), 1. Physikalisches Institut [Stuttgart], Universität Stuttgart [Stuttgart], Kumoh National Institute of Technology [Gumi], Kumoh National Institute of Technology [Gyeongsangbuk-do], Donostia International Physics Center (DIPC), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), SUPA School of Physics and Astronomy [Edinburgh], University of Edinburgh, Department of Physics, Princeton University (DPPU), Princeton University, Institute for Frontier Materials (IFM), Deakin University [Burwood], Department of Physics, Columbia University, Ikerbasque - Basque Foundation for Science, Basque Research and Technology Alliance (BRTA), University of York [York, UK], SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), University of Manchester [Manchester], Texas Tech University [Lubbock] (TTU), Department of Physics, University of Michigan, University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Institute for Quantum Computing [Waterloo] (IQC), University of Waterloo [Waterloo], Heriot-Watt University [Edinburgh] (HWU), Laboratory for Muon-Spin Spectroscopy (LMU), Paul Scherrer Institute (PSI), National High Magnetic Field Laboratory (NHMFL), Florida State University [Tallahassee] (FSU), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Princeton Institute for the Science and Technology of Materials, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Rice University [Houston], Donostia International Physics Center - DIPC (SPAIN), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU)-University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), and ANR-18-CE24-0007,MAGICVALLEY,Polarisation de vallée induite par couplage d'échange magnétique dans les matériaux 2D à grande échelle(2018)
Subjects: 2D magnetic materials, Magnetic Phenomena, neutron scattering, General Engineering, General Physics and Astronomy, Spintronics, Device engineering, Computing Methodologies, Magnetic imaging, atomistic spin dynamics, Topological properties, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], van der Waals, Heterostructures, Quantum Theory, General Materials Science, magneto-optical effect, Spin excitations, theory
Abstract: International audience; Magnetism in two-dimensional (2D) van der Waals (vdW) materials has recently emerged as one of the most promising areas in condensed matter research, with many exciting emerging properties and significant potential for applications ranging from topological magnonics to low-power spintronics, quantum computing, and optical communications. In the brief time after their discovery, 2D magnets have blossomed into a rich area for investigation, where fundamental concepts in magnetism are challenged by the behavior of spins that can develop at the single layer limit. However, much effort is still needed in multiple fronts before 2D magnets can be routinely used for practical implementations. In this comprehensive review, prominent authors with expertise in complementary fields of 2D magnetism (i.e., synthesis, device engineering, magneto-optics, imaging, transport, mechanics, spin excitations, and theory and simulations) have joined together to provide a genome of current knowledge and a guideline for future developments in 2D magnetic materials research.
Published: 2022
Full Text: View/download PDF

21. Determination of Cleavage Energy and Efficient Nanostructuring of Layered Materials by Atomic Force Microscopy

Author: Bertold Rasche, Julius Brunner, Tim Schramm, Madhav Prasad Ghimire, Ulrike Nitzsche, Bernd Büchner, Romain Giraud, Manuel Richter, Joseph Dufouleur, Institute of Physical Chemistry [Cologne], University of Cologne, Leibniz Institute for Solid State and Materials Research (IFW Dresden), Leibniz Association, Tribhuvan University, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden (IFW Dresden), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: Mechanical Engineering, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, Bioengineering, General Chemistry, Condensed Matter Physics
Abstract: International audience; A method is presented to use atomic force microscopy to measure the cleavage energy of van der Waals materials and similar quasi-two-dimensional materials. The cleavage energy of graphite is measured to be 0.36 J/m2, in good agreement with literature data. The same method yields a cleavage energy of 0.6 J/m2 for MoS2 as a representative of the dichalcogenides. In the case of the weak topological insulator Bi14Rh3I9 no cleavage energy is obtained, although cleavage is successful with an adapted approach. The cleavage energies of these materials are evaluated by means of density-functional calculations and literature data. This further validates the presented method and sets an upper limit of about 0.7 J/m2 to the cleavage energy that can be measured by the present setup. In addition, this method can be used as a tool for manipulating exfoliated flakes, prior to or after contacting, which may open a new route for the fabrication of nanostructures.
Published: 2022
Full Text: View/download PDF

22. Design-Time Exploration for Process, Environment and Aging Compensation Techniques for Low Power Reliable-Aware Design

Author: Lorena Anghel, Florian Cacho, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and STMicroelectronics [Crolles] (ST-CROLLES)
Subjects: Human-Computer Interaction, Computer Science (miscellaneous), [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS, Computer Science Applications, Information Systems
Abstract: International audience; Modern CMOS technologies such as advanced process FDSOI are affected by aging effects which can impact circuit functionality during lifetime operation. Indeed, due to system activity and usage dependence it is extremely difficult to establish a-priori sufficient guard bands for performance estimations, which leads either to large delay overestimation (and therefore loss of performances) or to reduced operating lifetime. In this paper, we propose an exploration of full adaptive AVS, ABB and combined supply and body bias techniques based on embedded monitors to obtain reliable functional operation, increased lifetime, while reducing the power consumption for the duration of the runtime. SPICE simulations performed on ARM processors show that large design margins in terms of area and power can be reduced, while keeping the target reliability and performance for the entire expected lifetime.
Published: 2022
Full Text: View/download PDF

23. The search for manganese incorporation in MoSe 2 monolayer epitaxially grown on graphene

Author: Maxime Gay, Minh-Tuan Dau, Céline Vergnaud, Alain Marty, Frédéric Bonell, Hervé Boukari, Colin Paillet, Bérangère Hyot, Hanako Okuno, Pierre Mallet, Jean-Yves Veuillen, Olivier Renault, Matthieu Jamet, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Nanophysique et Semiconducteurs (NPSC), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Nano-Electronique Quantique et Spectroscopie (QuNES), ANR-18-CE24-0007,MAGICVALLEY,Polarisation de vallée induite par couplage d'échange magnétique dans les matériaux 2D à grande échelle(2018), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), Nanophysique et Semiconducteurs (NEEL - NPSC), and Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES)
Subjects: Materials science, Graphene, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, Manganese, 2D materials, 021001 nanoscience & nanotechnology, Epitaxy, 01 natural sciences, law.invention, Crystallography, chemistry, law, 0103 physical sciences, Monolayer, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Magnetic doping, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Scanning tunneling microscopy, 010306 general physics, 0210 nano-technology, Molecular beam epitaxy, Transmission electron microscopy, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2022
Full Text: View/download PDF

24. Ferromagnetism and Rashba Spin–Orbit Coupling in the Two-Dimensional (V,Pt)Se2 Alloy

Author: Emilio Vélez-Fort, Ali Hallal, Roberto Sant, Thomas Guillet, Khasan Abdukayumov, Alain Marty, Céline Vergnaud, Jean-François Jacquot, Denis Jalabert, Jun Fujii, Ivana Vobornik, Julien Rault, Nicholas B. Brookes, Danilo Longo, Philippe Ohresser, Abdelkarim Ouerghi, Jean-Yves Veuillen, Pierre Mallet, Hervé Boukari, Hanako Okuno, Mairbek Chshiev, Frédéric Bonell, Matthieu Jamet, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), European Synchrotron Radiation Facility (ESRF), Conception d’Architectures Moléculaires et Processus Electroniques (CAMPE ), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Département Interfaces pour l'énergie, la Santé et l'Environnement (DIESE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Laboratorio TASC (IOM CNR), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), CNR Istituto Officina dei Materiali (IOM), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Nano-Electronique Quantique et Spectroscopie (NEEL - QuNES), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Nanophysique et Semiconducteurs (NEEL - NPSC), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), ANR-18-CE24-0007,MAGICVALLEY,Polarisation de vallée induite par couplage d'échange magnétique dans les matériaux 2D à grande échelle(2018), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), and European Project: 785219,H2020,GrapheneCore2(2018)
Subjects: Condensed Matter::Materials Science, Materials Chemistry, Electrochemistry, Condensed Matter::Strongly Correlated Electrons, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Electronic, Optical and Magnetic Materials
Abstract: 5 pages, 5 figures; International audience; We report on a two-dimensional (2D) V1–xPtxSe2 alloy that exhibits ferromagnetic order and Rashba spin–orbit coupling. Although ferromagnetism is absent in 1T-VSe2 because of the competition with the charge density wave phase, we demonstrate theoretically and experimentally that the substitution of vanadium by platinum in VSe2 (10–50%) to form a homogeneous 2D alloy restores ferromagnetic order down to one monolayer of V0.65Pt0.35Se2. Moreover, the presence of platinum atoms gives rise to Rashba spin–orbit coupling in (V,Pt)Se2, providing an original platform to study the interplay between ferromagnetism and spin–orbit coupling in the 2D limit.
Published: 2022
Full Text: View/download PDF

25. Bereziskii-Kosterlitz-Thouless transition in the Weyl system PtBi2

Author: Veyrat, Arthur, Labracherie, Valentin, Bashlakov, Dima, Caglieris, Federico, Facio, Jorge, Shipunov, Grigory, Charvin, Titouan, Acharya, Rohith, Naidyuk, Yurii, Giraud, Romain, van den Brink, Jeroen, Büchner, Bernd, Hess, Christian, Aswartham, Saicharan, Dufouleur, Joseph, Leibniz Institute for Solid State and Materials Research (IFW Dresden), Leibniz Association, B. Verkin Institute for Low Temperature Physics and Engineering (ILTPE), National Academy of Sciences of Ukraine (NASU), Centro Atómico Bariloche [Argentine], Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Comisión Nacional de Energía Atómica [ARGENTINA] (CNEA), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], 2D superconductivity, Condensed Matter::Superconductivity, quantum materials, Weyl semimetals, BKT transition, charge transport
Abstract: Symmetry breaking in topological matter has become in recent years a key concept in condensed matter physics to unveil novel electronic states. In this work, we predict that broken inversion symmetry and strong spin–orbit coupling in trigonal PtBi2 lead to a type-I Weyl semimetal band structure. Transport measurements show an unusually robust low dimensional superconductivity in thin exfoliated flakes up to 126 nm in thickness (with Tc ∼ 275–400 mK), which constitutes the first report and study of unambiguous superconductivity in a type-I Weyl semimetal. Remarkably, a Berezinskii-Kosterlitz-Thouless transition with TBKT ∼ 310 mK is revealed in up to 60 nm thick flakes, which is nearly an order of magnitude thicker than the rare examples of two-dimensional superconductors exhibiting such a transition. This makes PtBi2 an ideal platform to study low dimensional and unconventional superconductivity in topological semimetals.
Published: 2023
Full Text: View/download PDF

26. Dynamic imprinting of nanoscale topological phases into an antiferromagnet

Author: Leiviskä, Miina, Jenkins, Sarah, Evans, Richard F. L., Gusakova, Daria, Baltz, Vincent, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and University of York [York, UK]
Subjects: Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), FOS: Physical sciences, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract: Controlling the magnetic order of antiferromagnets is challenging due to the vanishing net magnetisation. For this reason, the study of topologically protected real-space states of antiferromagnets is restricted by the difficulty in nucleating such states. Here, using atomistic simulations we demonstrate how to nucleate predefined, localised spin textures in a thin film antiferromagnet, $\gamma$-IrMn$_3$. Utilising the exchange bias coupling between a ferromagnet and an antiferromagnet, we imprint the topological states on the former onto the latter by means of a thermal cycling procedure. The imprinted textures are shown to be stable against field perturbations. We also discuss how various material parameters affect the efficiency of the imprinting and the characteristics of the imprinted textures. This work paves way for further studies on topologically protected real-space phases in antiferromagnets and promotes the development of denser and faster spintronic devices.
Published: 2023

27. The 2022 applied physics by pioneering women

Author: Abad, B, Alberi, K, Ayers, KE, Badhulika, S, Ban, C, Béa, H, Béron, F, Cairney, J, Chang, JP, Charles, C, Creatore, M, Dong, H, Du, J, Egan, R, Everschor-Sitte, K, Foley, C, Fontcuberta I Morral, A, Jung, MH, Kim, H, Kurtz, S, Lee, J, Leitao, DC, Lemmer, K, Marschilok, AC, Mitu, B, Newman, BK, Owens, R, Pappa, AM, Park, Y, Peckham, M, Rossi, LM, Shim, SH, Siddiqui, SA, Son, JW, Spiga, S, Tsikata, S, Vianello, E, Wilson, K, Yuasa, H, Zardo, I, Zenyuk, I, Zhang, Y, Zhao, Y, Fluids and Flows, Plasma & Materials Processing, Interfaces in future energy technologies, EIRES Chem. for Sustainable Energy Systems, Physics of Nanostructures, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), DARPA TEE program through Grant No. MIPRHR0011831554, ANR-19-CE24-0019,ADMIS,Contrôle de l'interaction de Dzyaloshinskii-Moryia par champ électrique(2019), ANR-16-CE24-0018,ELECSPIN,Dispositifs Spintronique assistés par champ électrique(2016), Abad, B [0000-0001-7589-7973], Alberi, K [0000-0002-5236-5568], Badhulika, S [0000-0003-3237-3031], Ban, C [0000-0002-1472-1496], Béa, H [0000-0002-3762-4795], Béron, F [0000-0002-4926-2963], Cairney, J [0000-0003-4564-2675], Chang, JP [0000-0001-8482-5744], Creatore, M [0000-0002-5318-8954], Dong, H [0000-0002-6444-1134], Du, J [0000-0001-8111-9588], Everschor-Sitte, K [0000-0001-8767-6633], Fontcuberta i Morral, A [0000-0002-5070-2196], Lee, J [0000-0002-3312-6369], Leitao, DC [0000-0001-8419-2967], Lemmer, K [0000-0003-1477-6232], Owens, R [0000-0001-7856-2108], Pappa, AM [0000-0002-7980-4073], Peckham, M [0000-0002-3754-2028], Rossi, LM [0000-0001-7679-0852], Shim, SH [0000-0001-9964-7231], Son, JW [0000-0002-5310-0633], Spiga, S [0000-0001-7293-7503], Tsikata, S [0000-0001-5104-0676], Vianello, E [0000-0002-8868-9951], Wilson, K [0000-0003-4873-708X], Yuasa, H [0000-0002-3461-7362], Zardo, I [0000-0002-8685-2305], Zenyuk, I [0000-0002-1612-0475], Zhang, Y [0000-0003-1319-3270], and Apollo - University of Cambridge Repository
Subjects: [PHYS]Physics [physics], cathode, applied physics, Acoustics and Ultrasonics, magnesium, Physik (inkl. Astronomie), Condensed Matter Physics, pioneering, dc squid, efficient, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, power, thermal transport, microscopy, squid magnetometers, fuel-cell, women, performance
Abstract: Funder: Dutch NWO Aspasia program, Funder: University of Colorado Boulder; doi: http://dx.doi.org/10.13039/100007493, Funder: FSE/POPH, Women have made significant contributions to applied physics research and development, and their participation is vital to continued progress. Recognizing these contributions is important for encouraging increased involvement and creating an equitable environment in which women can thrive. This Roadmap on Women in Applied Physics, written by women scientists and engineers, is intended to celebrate women’s accomplishments, highlight established and early career researchers enlarging the boundaries in their respective fields, and promote increased visibility for the impact women have on applied physics research. Perspectives cover the topics of plasma materials processing and propulsion, super-resolution microscopy, bioelectronics, spintronics, superconducting quantum interference device technology, quantum materials, 2D materials, catalysis and surface science, fuel cells, batteries, photovoltaics, neuromorphic computing and devices, nanophotonics and nanophononics, and nanomagnetism. Our intent is to inspire more women to enter these fields and encourage an atmosphere of inclusion within the scientific community.
Published: 2023
Full Text: View/download PDF

28. Complete identification of spin-wave eigenmodes excited by parametric pumping in YIG microdisks

Author: Srivastava, Titiksha, Merbouche, Hugo, Yemeli, Igor Ngouagnia, Beaulieu, Nathan, Youssef, Jamal Ben, Munoz, Manuel, Che, Ping, Bortolotti, Paolo, Cros, Vincent, Klein, Olivier, Sangiao, Soraya, De Teresa, Jose Maria, Demokritov, Sergej, Demidov, Vladislav, Anane, Abdelmadjid, Serpico, Claudio, d'Aquino, Massimiliano, de Loubens, Gregoire, Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire Nano-Magnétisme et Oxydes (LNO), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institute for Applied Physics and Center for Nanotechnology, Westfälische Wilhelms-Universität Münster = University of Münster (WWU), Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Instituto de Nanociencia y Materiales de Aragón (INMA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de Zaragossa, Université de Naples - Frederico II, ANR-10-LABX-0035,Nano-Saclay,Paris-Saclay multidisciplinary Nano-Lab(2010), ANR-18-CE24-0021,MAESTRO,Excitation de magnons dans le régime fortement hors d'équilibre(2018), and European Project: 899646,H2020-FETOPEN-KNET
Subjects: Condensed Matter - Mesoscale and Nanoscale Physics, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Mesoscale and Nanoscale Physics (cond-mat.mes-hall), FOS: Physical sciences, Applied Physics (physics.app-ph), Physics - Applied Physics
Abstract: We present the parametric excitation of spin-wave modes in YIG micro-disks via parallel pumping. Their spectroscopy is performed using magnetic resonance force microscopy (MRFM), while their spatial profiles are determined by micro-focus Brillouin light scattering (BLS). We observe that almost all the fundamental eigenmodes of an in-plane magnetized YIG micro-disk, calculated using a micromagnetic eigenmode solver, can be excited using the parallel pumping scheme, as opposed to the transverse one. The comparison between the MRFM and BLS data on one side, and the simulations on the other side, provides the complete spectroscopic labeling of over 40 parametrically excited modes. Our findings could be promising for spin-wave-based computation schemes, in which the amplitudes of a large number of spin-wave modes have to be controlled., 6 pages, 4 figures
Published: 2023

29. Non-local magnon transconductance in extended magnetic insulating films

Author: Kohno, Ryuhei, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Université Grenoble Alpes [2020-....], Olivier Klein, and Laurent Vila
Subjects: Magnonics, Spintronique, Spintronics, Spin wave, Yig, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Ondes de spin
Abstract: Spin insulatronics is an emerging field of research, which aims at exploiting electrical insulators as a novel transport medium that can propagate pure spin current with the benefit of developing more energy efficient computers and other electronics. The vision is to replace the delocalized electrons present in metallic materials by propagating spin-waves, which transport the spin without any Joule dissipation. In this thesis, we investigate the fundamentals of magnon excitation and propagation in extended magnetic insulating thin films. We focus our interest on the characteristics of magnon trans-conductance in thin magnetic garnet films excited by spin transfer effects (spin orbit torques from an adjacent Pt wire by the spin Hall effect) by using devices consisting of two Pt wires deposited on extended ferromagnetic insulators acting as an emitter and a collector of magnons respectively.The absence of Joule dissipation usually gifts the dielectric materials with very low magnetic damping, which is associated with a high propensity for magnons to behave nonlinearly. This effect could be exploited for spin diodes, spin amplifiers or spin rectifiers of microwave signals. We analyze the origin of the spin diode conduction which introduces an asymmetry of the spin transport properties. The feature is rooted in the variation of the density of low-lying spin excitations via an electrical shift of the magnon chemical potential. As the intensity of the spin transfer increases, the transport properties of low-energy magnon go through 3 distinct regimes: i) at low currents, where the spin current is a linear function of the electrical current, the spin transport is ballistic and set by the film thickness: ii) for amplitudes of the order of the damping compensation threshold, it switches to a highly correlated regime limited by magnon-magnon relaxation process and marked by a saturation of the magnon transconductance. Here the main bias, that controls the magnon density, is thermal fluctuations beneath the emitter. iii) As the temperature under the emitter approaches the Curie temperature, scattering with high-energy magnons dominates, leading to diffusive transport. We note that such a sequence of transport regimes bears an analogy with electron hydrodynamic transport in ultra-pure media.The magnon transconductance is carried by spin excitation covering a wide energy range. It will be shown that for all practical purposes this picture can be simplified in a two-fluid model which only takes into account magnons at both ends of the energy spectrum: i) a large portion of high-energy magnons at thermal energy, with a characteristic decay length in a sub-micronic range, and ii) a small portion of low-energy magnons, with a characteristic decay length in a micronic range. Those distinct transport characteristics provide a way to filter out the high-energy magnons and to exploit the functionality of the low-energy magnons. The latter may become the dominant fluid for example at a large intensity of injection to be in the regime of spin diode effect, or at a large distance from the emitter.Based on the acquired knowledge, we seek new functionalities by controlling the transport with an additional electrode. We demonstrate the amplification of the transports of low-energy magnons by locally heating the collector. The conduction is enhanced by about a factor of 4. Micromagnetic simulations also demonstrate an enhancement of the oscillation amplitude by reducing the magnetization locally. They reveal a formation of standing waves between the two Pt wires, suggesting that the local magnetization gradient can act as a mirror for the low-energy magnons.Overall we believe that this thesis work contributes to improving the understanding of magnon transports provided by spin transfer effects in extended geometries. In the long run this will contribute to the development of more realistic insulatronic circuits.; L'insulatronique de spin est un nouveau domaine de recherche, qui vise à exploiter les isolants électriques comme média pour le transport de pur courant de spin, dans le but de développer des composants électroniques plus efficaces sur le plan énergétique. La vision est de remplacer les électrons délocalisés présents dans les matériaux métalliques par des ondes de spin propagatives, qui transportent le spin sans aucune dissipation ohmique. Dans cette thèse, nous étudions les principes fondamentaux de l'excitation et de la propagation des magnons dans des films minces d'isolants magnétiques étendus. Nous concentrons notre étude sur la transconductance des magnons dans les films minces de grenat magnétique excités par des effets de transfert de spin (couple de transfert de spin par un fil de Pt adjacent grâce à l'effet Hall de spin) en utilisant des dispositifs constitués de deux fils de Pt déposés sur les films agissant respectivement comme émetteur et collecteur de magnons.L'absence de dissipation par effet Joule confère généralement aux matériaux isolants un très faible amortissement magnétique, qui est associé à une forte propension des magnons à se comporter de manière non-linéaire. Cet effet peut être exploité pour des diodes de spin, des amplificateurs de spin ou des redresseurs de spin de signaux micro-ondes. Nous analysons l'origine de cet effet qui introduit une asymétrie des propriétés de transport. En effet, la variation de la densité d'excitations de spin de basse énergie via un déplacement électrique du potentiel chimique de magnon est responsable. Les propriétés de transport des magnons à basse énergie passent par trois régimes distincts :i) à faible courant, où le courant de spin est une fonction linéaire du courant électrique, le transport de spin est balistique et déterminé par l'épaisseur du film :ii) pour des amplitudes de l'ordre du seuil de compensation de l'amortissement, il passe à un régime hautement corrélé par le processus de relaxation magnon-magnon. :iii) Lorsque la température sous l'émetteur approche la température de Curie, la diffusion avec des magnons à hautes énergies domine, ce qui conduit à un transport diffusif. Nous notons qu'une telle séquence de différents régimes de transport est analogue au transport hydrodynamique des électrons dans les milieux ultra-purs.Cependant, le transconductance des magnons est portée par une excitation de spin couvrant une large gamme d'énergie. On montrera que cette image peut être simplifiée de façon drastique dans un modèle à deux fluides qui ne prend en compte que les magnons aux deux extrémités du spectre d'énergie : i) une grande partie des magnons de haute énergie, proche de l'énergie thermique, avec une longueur caractéristique de propagation dans la gamme sub-micronique, et ii) une petite partie des magnons de basse énergie, avec une longueur caractéristique de propagation dans la gamme micronique. Ces caractéristiques de transport distinctes permettent de filtrer les magnons et d'exploiter les fonctionnalités spécifiques aux magnons à basse énergie.Sur la base de ces connaissances, nous cherchons de nouvelles fonctionnalités en contrôlant le transport avec une électrode supplémentaire. Nous démontrons l'amplification de la part du transport porté par les magnons de basse énergie en chauffant localement le collecteur. La conduction peut être améliorée d'un facteur 4 environ en chauffant le collecteur. Les simulations micromagnétiques révèlent la formation d'ondes stationnaires entre les deux fils de Pt, suggérant que le gradient de magnétisation local peut agir comme un miroir pour les magnons de basse énergie.Dans l'ensemble, nous nous persuadons que ce travail de thèse contribue à améliorer la compréhension des transports de magnons induits par les effets de transfert de spin dans les géométries étendues. A long terme, cela contribuera au développement de circuits insulatroniques plus réalistes.
Published: 2023

30. Electrical characterization of the azimuthal anisotropy of $(\mathrm{Ni}_x\mathrm{Co}_{1-x})\mathrm{B}$-based ferromagnetic nanotubes

Author: Tiwari, Dhananjay, Scheuerlein, Martin Christoph, Jaber, Mahdi, Gautier, Eric, Vila, Laurent, Attané, Jean-Philippe, Schöbitz, Michael, Masseboeuf, Aurélien, Hellmann, Tim, Hofmann, Jan P., Ensinger, Wolfgang, Fruchart, Olivier, Micro et NanoMagnétisme (NEEL - MNM), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Department of Materials and Earth Sciences [Darmstadt], Technische Universität Darmstadt - Technical University of Darmstadt (TU Darmstadt), and ANR-18-CE92-0045,C3DS,Chimie pour une spintronique 3D(2018)
Subjects: [PHYS]Physics [physics], Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), FOS: Physical sciences
Abstract: We report on the structural, electric and magnetic properties of $(\mathrm{Ni}_x\mathrm{Co}_{1-x})\mathrm{B}$ ferromagnetic nanotubes, displaying azimuthal magnetization. The tubes are fabricated using electroless plating in polycarbonate porous templates, with lengths several tens of micrometers, diameters from 100nm to 500nm and wall thicknesses from 10nm to 80nm. The resistivity is $\sim 1.5\times10^{-6}\mathrm{\Omega/m}$, and the anisotropic magnetoresistance~(AMR) of 0.2-0.3%, one order of magnitude larger~(resp. smaller) than in the bulk material, which we attribute to the resistance at grain boundaries. We determined the azimuthal anisotropy field from M(H) AMR loops of single tubes contacted electrically. Its magnitude is around 10mT, and tends to increase with the tube wall thickness, as well as the Co content. However, surprisingly it does not dependent much on the diameter nor on the curvature., Comment: 12 pages, 10 figures, includes methods and appendix
Published: 2023

31. Competitive actions of MnSi in the epitaxial growth of Mn5Si3 thin films on Si(111)

Author: Kounta, Ismaïla, Reichlova, Helena, Kriegner, Dominik, Lopes Seeger, Rafael, Bad'Ura, Antonin, Leiviska, Miina, Boussadi, Amine, Heresanu, Vasile, Bertaina, Sylvain, Petit, Matthieu, Schmoranzerova, Eva, Smejkal, Libor, Sinova, Jairo, Jungwirth, Tomas, Baltz, Vincent, Goennenwein, Sebastian, Michez, Lisa, Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU), Institut für Festkörper- und Materialphysik, Technische Universität Dresden, Technische Universität Dresden = Dresden University of Technology (TU Dresden), Dresden-Würzburg Center of Excellence on Complexity and Topology in Quantum Matte (ct.qmat), Institute of Physics of the Czech Academy of Sciences (FZU / CAS), Czech Academy of Sciences [Prague] (CAS), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Faculty of Mathematics and Physics [Charles University of Praha], Charles University [Prague] (CU), Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Polytech Marseille (AMU POLYTECH), Institut für Physik Johannes Gutenberg Universität, Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), School of Physics and Astronomy, University of Nottingham, Fachbereich Physik, Universität Konstanz, Universitätsstraße 10, D-78453 Konstanz, Germany ( Fachbereich Physik, Universität Konstanz), Fachbereich Physik, Universität Konstanz, GACR Grant No. 22-17899K, Lumina Quaeruntur fellowship of the Czech Academy of Science (Grant No. LQ100102201), Elasto-Q-Mat (DFG SFB TRR 288), and ANR-20-CE92-0049,MATHEEIAS,Effets magnéto-thermo-électriques en électronique de spin antiferromagnétique(2020)
Subjects: Mn5Si3, Antiferromagnetism, Interface & surface thermodynamics, Anomalous hall effect, MBE - Molecular Beam Epitaxy, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Spintronics
Abstract: International audience; Some magnetically ordered phases of the Mn5Si3 crystal are proving to be prototypes for the study of thenew fundamental spin physics related to the spontaneous breaking of the time-reversal symmetry despite a zeronet magnetization. Here, we report on a route to grow epitaxial Mn5Si3 thin films on Si(111). To this end, weuse Mn and Si codeposition in a molecular beam epitaxy system and carefully tune the deposition rates, thegrowth temperature, and the annealing temperature. We assessed the silicide phase-formation and morphologyusing reflection high-energy electron diffraction, x-ray diffraction, high-resolution transmission electron mi-croscopy (HRTEM) and atomic force microscopy. Layers containing only Mn5Si3 could be stabilized undervery restrictive conditions, by tuning the Mn/Si flux ratio to match the compound stoichiometry and adjustingthe substrate temperature during growth to 443 K. HRTEM imaging revealed the existence of an interfacialamorphous layer of few nanometers thickness. Annealing the heterostructure up to 573 K led to the formationof MnSi at the vicinity of the Mn5Si3/Si(111) interface, which significantly reduced the nucleation barrier ofMn5Si3. High-quality crystalline Mn5Si3 thin films were then formed with the following epitaxial relationships:Mn5Si3 (0001)[011̄0]//MnSi(111)[2̄11]//Si(111)[11̄0]. Our experiments showed that the formation of MnSi isenhanced at a growth temperature above 473 K or for a longer annealing step, while the crystalline quality of theMn5Si3 overlayer is correspondingly degraded leading to textured thin films. The growth pathways and structuralproperties of the manganese silicides can be rationalized in terms of reactions maximizing the free-energylowering rate. Moreover, we found that the magnetic and the magnetotransport properties can be used as anefficient tool to track both Mn5Si3 crystallinity and proportion in the deposited layers.
Published: 2023
Full Text: View/download PDF

32. Control of skyrmion chirality in Ta/FeCoB/TaO$_x$ trilayers by TaO$_x$ oxidation and FeCoB thickness

Author: Kumar, Raj, Fillion, C.E., Lovery, Bertrand, Benguettat-El Mokhtari, I., Joumard, Isabelle, Auffret, Stéphane, Ranno, Laurent, Roussigné, Yves, Chérif, S.M., Stashkevich, Andrey, Belmeguenai, Mohamed, Baraduc, Claire, Béa, Hélène, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Laboratoire des Sciences des Procédés et des Matériaux (LSPM), Institut Galilée-Université Sorbonne Paris Cité (USPC)-Centre National de la Recherche Scientifique (CNRS)-Université Sorbonne Paris Nord, Micro et NanoMagnétisme (NEEL - MNM), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), ANR-19-CE24-0019,ADMIS,Contrôle de l'interaction de Dzyaloshinskii-Moryia par champ électrique(2019), and ANR-16-CE24-0018,ELECSPIN,Dispositifs Spintronique assistés par champ électrique(2016)
Subjects: Dzyaloshinskii-Moriya interaction, thin films, skyrmions, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], electric field control, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics
Abstract: International audience; Skyrmions are magnetic bubbles with nontrivial topology envisioned as data bits for ultrafast and power efficient spintronic memory and logic devices. They may be stabilized in heavy metal/ferromagnetic/oxide trilayer systems. The skyrmion chirality is then determined by the sign of interfacial Dzyaloshinskii-Moriya interaction (DMI). Nevertheless, for apparently identical systems, there is some controversy about the DMI sign. Here we show that the degree of oxidation of the top interface and the thickness of the ferromagnetic layer play a major role. Using Brillouin light scattering measurements in Ta/FeCoB/TaO$_x$ trilayers, we have demonstrated a sign change of the DMI with the degree of oxidation of FeCoB/TaO$_x$ interface. Using polar magneto-optical Kerr effect microscopy, we consistently observed a reversal of the direction of current-induced motion of skyrmions with the oxidation level of TaOx, attributed to their chirality reversal. In addition, a second chirality reversal is observed when changing the FeCoB thickness, probably due to the proximity of the two FeCoB interfaces in the ultrathin case. By properly tuning the chirality of the skyrmion, the spin transfer and spin orbit torques combine constructively to enhance the skyrmion velocity. These observations thus allow envisioning an optimization of the material parameters producing highly mobile skyrmions in this system and could be extended to other stacks. This chirality control also enables a more versatile manipulation of skyrmions and paves the way towards multidirectional devices.
Published: 2023
Full Text: View/download PDF

33. Hybridization and localized flat band in the WSe2/MoSe2 heterobilayer

Author: Lama Khalil, Debora Pierucci, Emilio Velez-Fort, José Avila, Céline Vergnaud, Pavel Dudin, Fabrice Oehler, Julien Chaste, Matthieu Jamet, Emmanuel Lhuillier, Marco Pala, Abdelkarim Ouerghi, Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Physico-chimie et dynamique des surfaces (INSP-E6), Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE24-0030,RhomboG,Propriétés electroniques de couches minces de graphite rhombohedrique(2017), ANR-18-CE24-0007,MAGICVALLEY,Polarisation de vallée induite par couplage d'échange magnétique dans les matériaux 2D à grande échelle(2018), ANR-19-CE09-0026,GRaSkop,Tuning Giant Rashba Spin-Orbit Coupling in Polar Single Layer Transition Metal Dichalcogenides(2019), and ANR-10-LABX-0035,Nano-Saclay,Paris-Saclay multidisciplinary Nano-Lab(2010)
Subjects: perovskite oxides, [PHYS]Physics [physics], MBE, Mechanical Engineering, quantum materials, ferroelectrics, Bioengineering, General Chemistry, 2D materials, heterostructures, Mechanics of Materials, transition-metal dichalcogenides, General Materials Science, Electrical and Electronic Engineering, angle-resolved photoemission spectroscopy, XPS/ARPES, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Abstract: Nearly localized moiré flat bands in momentum space, arising at particular twist angles, are the key to achieve correlated effects in transition-metal dichalcogenides. Here, we use angle-resolved photoemission spectroscopy (ARPES) to visualize the presence of a flat band near the Fermi level of van der Waals WSe2/MoSe2 heterobilayer grown by molecular beam epitaxy. This flat band is localized near the Fermi level and has a width of several hundred meVs. By combining ARPES measurements with density functional theory calculations, we confirm the coexistence of different domains, namely the reference 2H stacking without layer misorientation and regions with arbitrary twist angles. For the 2H-stacked heterobilayer, our ARPES results show strong interlayer hybridization effects, further confirmed by complementary micro- Raman spectroscopy measurements. The spin-splitting of the valence band at K is determined to be 470 meV. The valence band maximum (VBM) position of the heterobilayer is located at the Γ point. The energy difference between the VBM at Γ and the K point is of −60 meV, which is a stark difference compared to individual single monolayer WSe2 and monolayer WSe2, showing both a VBM at K.
Published: 2023
Full Text: View/download PDF

34. A material view on extrinsic magnetic domain wall pinning in cylindrical CoNi nanowires

Author: Michael Schöbitz, Ondrej Novotný, Beatrix Trapp, Sebastian Bochmann, Laurent Cagnon, Christophe Thirion, Aurélien Massebœuf, Eric Mossang, Olivier Fruchart, Julien Bachmann, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Micro et NanoMagnétisme (NEEL - MNM), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), X'Press : diffraction et hautes pressions (NEEL - X'Press), Department of Health Technology, Technical University of Denmark, Danmarks Tekniske Universitet = Technical University of Denmark (DTU), CNRS-CEA 'METSA' French network (FR CNRS 3507), ANR-10-LABX-0051,LANEF,Laboratory of Alliances on Nanosciences - Energy for the Future(2010), Micro et NanoMagnétisme (MNM), X'Press (X'Press), Saint Petersburg State University (SPBU), Fruchart, Olivier, and Laboratoires d'excellence - Laboratory of Alliances on Nanosciences - Energy for the Future - - LANEF2010 - ANR-10-LABX-0051 - LABX - VALID
Subjects: Condensed Matter - Materials Science, General Energy, Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Physical and Theoretical Chemistry, [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials
Abstract: Speed and reliability of magnetic domain wall (DW) motion are key parameters that must be controlled to realize the full potential of DW-based magnetic devices for logic and memory applications. A major hindrance to this is extrinsic DW pinning at specific sites related to shape and material defects, which may be present even if the sample synthesis is well controlled. Understanding the origin of DW pinning and reducing it is especially desirable in electrochemically-deposited cylindrical magnetic nanowires (NWs), for which measurements of the fascinating physics predicted by theoretical computation have been inhibited by significant pinning. We experimentally investigate DW pinning in Co$_x$Ni$_{100-x}$ NWs, by applying quasistatic magnetic fields. Wire compositions were varied with $x=20,30,40$, while the microstructure was changed by annealing or varying the pH of the electrolyte for deposition. We conclude that pinning due to grain boundaries is the dominant mechanism, decreasing inversely with both the spontaneous magnetization and grain size. Second-order effects include inhomogeneities in lattice strain and the residual magnetocrystalline anisotropy. Surface roughness, dislocations and impurities are not expected to play a significant role in DW pinning in these wire samples., Comment: 10 pages, 4 figures, regular manuscript
Published: 2023
Full Text: View/download PDF

35. Spin-Orbit Readout Using Thin Films of Topological Insulator Sb2Te3 Deposited by Industrial Magnetron Sputtering

Author: Teresi, S., Sebe, N., Frottier, T., Patterson, J., Kandazoglou, A., Noël, P., Sgarro, P., Térébénec, D., Bernier, N., Hippert, F., Attané, J. -P., Vila, L., Noé, P., Cosset-Chéneau, M., SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Condensed Matter - Materials Science, topological insulators, Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), spin-orbit read-out, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, spin-charge interconversion, spin-logic devices, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Abstract: Driving a spin-logic circuit requires the production of a large output signal by spin-charge interconversion in spin-orbit readout devices. This should be possible by using topological insulators, which are known for their high spin-charge interconversion efficiency. However, high-quality topological insulators have so far only been obtained on a small scale, or with large scale deposition techniques that are not compatible with conventional industrial deposition processes. The nanopatterning and electrical spin injection into these materials have also proven difficult due to their fragile structure and low spin conductance. The fabrication of a spin-orbit readout device from the topological insulator Sb2Te3 deposited by large-scale industrial magnetron sputtering on SiO2 is presented. Despite a modification of the Sb2Te3 layer structural properties during the device nanofabrication, a sizeable output voltage is measured that can be unambiguously ascribed to a spin-charge interconversion process. The results pave the way for the integration of layered van der Waals materials in spin-logic devices., Advanced Functional Materials, ISSN:1616-301X, ISSN:1616-3028
Published: 2023

36. Backpropagation-based learning techniques for deep spiking neural networks: a survey

Author: Manon Dampfhoffer, Thomas Mesquida, Alexandre Valentian, Lorena Anghel, Département Systèmes et Circuits Intégrés Numériques (DSCIN), Laboratoire d'Intégration des Systèmes et des Technologies (LIST (CEA)), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: [INFO.INFO-LG]Computer Science [cs]/Machine Learning [cs.LG], Artificial Intelligence, Computer Networks and Communications, [INFO.INFO-NE]Computer Science [cs]/Neural and Evolutionary Computing [cs.NE], Software, Computer Science Applications
Abstract: International audience; With the adoption of smart systems, artificial neural networks (ANNs) have become ubiquitous. Conventional ANN implementations have high energy consumption, limiting their use in embedded and mobile applications. Spiking neural networks (SNNs) mimic the dynamics of biological neural networks by distributing information over time through binary spikes. Neuromorphic hardware has emerged to leverage the characteristics of SNNs, such as asynchronous processing and high activation sparsity. Therefore, SNNs have recently gained interest in the machine learning community as a brain-inspired alternative to ANNs for low-power applications. However, the discrete representation of the information makes the training of SNNs by backpropagation-based techniques challenging. In this survey, we review training strategies for deep SNNs targeting deep learning applications such as image processing. We start with methods based on the conversion from an ANN to an SNN and compare these with backpropagation-based techniques. We propose a new taxonomy of spiking backpropagation algorithms into three categories, namely, spatial, spatiotemporal, and single-spike approaches. In addition, we analyze different strategies to improve accuracy, latency, and sparsity, such as regularization methods, training hybridization, and tuning of the parameters specific to the SNN neuron model. We highlight the impact of input encoding, network architecture, and training strategy on the accuracy–latency tradeoff. Finally, in light of the remaining challenges for accurate and efficient SNN solutions, we emphasize the importance of joint hardware–software codevelopment.
Published: 2023
Full Text: View/download PDF

37. Spin-orbit torque switching in 2D ferromagnet / topological insulator heterostructure grown by molecular beam epitaxy

Author: Guillet, Thomas, Galcera, Regina V., Sierra, Juan F., Costache, Marius V., Jamet, Matthieu, Bonell, Frédéric, Valenzuela, Sergio O., ICN2 - Institut Catala de Nanociencia i Nanotecnologia (ICN2), Universitat Autònoma de Barcelona (UAB), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), ANR-20-CE24-0015,ELMAX,Contrôle électrique de l'aimantation dans les hétérostructures van der Waals épitaxiées(2020), ANR-21-GRF1-0005,MNEMOSYN,Mémoires magnétiques 2D: croissance large-échelle et opération électrique hybride(2021), European Project: 881603,H2020,H2020-SGA-FET-GRAPHENE-2019, GrapheneCore3(2020), European Project: 840588,GRISOTO, and European Project: 754510,PROBIST
Subjects: Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), FOS: Physical sciences, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Abstract: Topological insulators (TIs) are a promising class of materials for manipulating the magnetization of an adjacent ferromagnet (FM) through the spin-orbit torque (SOT) mechanism. However, current studies combining TIs with conventional FMs present large device-to-device variations, resulting in a broad distribution of SOT magnitudes. It has been identified that the interfacial quality between the TI and the FM is of utmost importance in determining the nature and efficiency of the SOT. To optimize the SOT magnitude and enable ultra-low-power magnetization switching, an atomically smooth interface is necessary. To this end, we have developed the growth of a full van der Waals FM/TI heterostructure by molecular beam epitaxy. The compensated TI (Bi0.4Sb0.6)2Te3 and ferromagnetic Fe3GeTe2 (FGT) were chosen because of their exceptional crystalline quality, low carrier concentration in BST and relatively large Curie temperature and perpendicular magnetic anisotropy in FGT. We characterized the magnitude of the SOTs by using thorough harmonic magnetotransport measurements and showed that the magnetization of an ultrathin FGT film could be switched with a current density Jc < 10^10 A/m^2. In comparison to previous studies utilizing traditional FMs, our findings are highly reliable, displaying little to no variation between devices.
Published: 2023
Full Text: View/download PDF

38. Gradient-Induced Dzyaloshinskii–Moriya Interaction

Author: Jinghua Liang, Mairbek Chshiev, Albert Fert, Hongxin Yang, National Laboratory of Solid State Microstructures [Nanjing University] (LSSMS), Nanjing University (NJU), Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), and THALES [France]-Centre National de la Recherche Scientifique (CNRS)
Subjects: Condensed Matter - Materials Science, Torque, Mechanical Engineering, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, General Materials Science, Bioengineering, General Chemistry, Condensed Matter Physics
Abstract: The Dzyaloshinskii-Moriya interaction (DMI) that arises in the magnetic systems with broken inversion symmetry plays an essential role in topological spintronics. Here, by means of atomistic spin calculations, we study an intriguing type of DMI (g-DMI) that emerges in the films with composition gradient. We show that both the strength and chirality of g-DMI can be controlled by the composition gradient even in the disordered system. The layer-resolved analysis of g-DMI unveils its additive nature inside the bulk layers and clarifies the linear thickness dependence of g-DMI observed in experiments. Furthermore, we demonstrate the g-DMI induced chiral magnetic structures, such as spin spirals and skyrmions, and the g-DMI driven field-free spin-orbit torque (SOT) switching, both of which are crucial towards practical device application. These results elucidate the underlying mechanisms of g-DMI and open up a new way to engineer the topological magnetic textures., in production in Nano Letters
Published: 2022
Full Text: View/download PDF

39. Artificial Graphene Spin Polarized Electrode for Magnetic Tunnel Junctions

Author: Victor Zatko, Regina Galceran, Marta Galbiati, Julian Peiro, Florian Godel, Lisa-Marie Kern, David Perconte, Fatima Ibrahim, Ali Hallal, Mairbek Chshiev, Benjamin Martinez, Carlos Frontera, Lluìs Balcells, Piran R. Kidambi, John Robertson, Stephan Hofmann, Sophie Collin, Frédéric Petroff, Marie-Blandine Martin, Bruno Dlubak, Pierre Seneor, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), ICN2 - Institut Catala de Nanociencia i Nanotecnologia (ICN2), Universitat Autònoma de Barcelona (UAB), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Institut de Ciència de Materials de Barcelona (ICMAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Vanderbilt University [Nashville], University of Cambridge [UK] (CAM), ANR-19-CE09-0028,MIXES,Hétérostructures de van der Waals à dimensions mixtes pour l'électronique et la spintronique(2019), ANR-19-CE24-0015,STEM2D,Emetteurs THz de type synchrotron à base de matériaux 2D ondulés(2019), European Commission, Engineering and Physical Sciences Research Council (UK), Agence Nationale de la Recherche (France), Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Ciencia e Innovación (España), Zatko, Victor, Godel, Florian, Kern, Lisa-Marie, Chshiev, Mairbek, Frontera, Carlos, Kidambi, Piran R., Hofmann, Stephan, and Dlubak, Bruno
Subjects: Mechanical Engineering, graphene, General Materials Science, Bioengineering, General Chemistry, proximity effects, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Condensed Matter Physics, 2D materials, spin polarization
Abstract: 2D materials offer the ability to expose their electronic structure to manipulations by a proximity effect. This could be harnessed to craft properties of 2D interfaces and van der Waals heterostructures in devices and quantum materials. We explore the possibility to create an artificial spin polarized electrode from graphene through proximity interaction with a ferromagnetic insulator to be used in a magnetic tunnel junction (MTJ). Ferromagnetic insulator/graphene artificial electrodes were fabricated and integrated in MTJs based on spin analyzers. Evidence of the emergence of spin polarization in proximitized graphene layers was observed through the occurrence of tunnel magnetoresistance. We deduced a spin dependent splitting of graphene's Dirac band structure (∼15 meV) induced by the proximity effect, potentially leading to full spin polarization and opening the way to gating. The extracted spin signals illustrate the potential of 2D quantum materials based on proximity effects to craft spintronics functionalities, from vertical MTJs memory cells to logic circuits., This work has received funding from the European Union’s H2020 Future and Emerging Technologies “Graphene Flagship” (Grant Core3 No. 881603), “SINFONIA” (No. 881603) projects and a Grant Agreement Marie Skłodowska Curie “ITN Spinograph” (No. 697904), as well as from EPSRC (EP/P005152/1, EP/K016636/1). This research is supported by a public grant overseen by the French National Research Agency (ANR) as part of the “Investissements d’Avenir” program Labex NanoSaclay (ANR-10-LABX-0035), as well as grants STEM2D (ANR-19-CE24-0015), MIXES (ANR-19-CE09-0028), and by the Flag-ERA JTC 2019 project “SOGraphMEM” (ANR-19-GRFI-0001-07). This work has also received fundings from the “Spanish ministry of Science and Innovation” through “Severo Ochoa” (CEX2019-000917-S) and “OXISOT” (PID2021-128410OB-I00)., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).
Published: 2022
Full Text: View/download PDF

40. Binary Bayesian Neural Networks for Efficient Uncertainty Estimation Leveraging Inherent Stochasticity of Spintronic Devices

Author: Tuhin, Soyed, Danouchi, Kamal, Münch, Christopher, Prenat, Guillaume, Anghel, Lorena, Tahoori, Mehdi, Neural, Bayesian, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Karlsruhe Institute of Technology (KIT), Association for Computing machinery, and ANR-21-FAI1-0008,NEUSPIN,Conception d'un système intégré sur puce neuromorphique basé sur la spintronique à très faible consommation(2021)
Subjects: Dropout, Magnetic Tunnel Junction, Spintronics, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, [SPI.TRON]Engineering Sciences [physics]/Electronics, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI]
Abstract: International audience; In the age of automation, machine learning systems for real-time critical decisions in various domains such as autonomous driving are at an all-time high. Predictive uncertainty allows a machine learning system to make more insightful decisions by avoiding blind predictions. Algorithmically, Bayesian neural networks (BayNNs) based on dropout are principled methods for estimating predictive uncertainty in a machine learning application. However, the computational cost and power consumption make the use of BayNNs on embedded hardware unattractive. Hardware accelerators withemerging non-volatile resistive memories (NVMs) such as Magnetic Tunnel Junction (MTJ) in conjunction with quantized models are aninteresting option for efficient implementations of such a system. Binary BayNNs are a desirable alternative that can provide predictive uncertainty efficiently by combining the benefits of quantization and hardware acceleration. In this paper, propose for the first time the binary bayesian neural network (BayBNN) using dropout-based approximation, and we leverage the inherent randomness of spin-tronic devices for in-memory Bayesian inference. Our proposed method can detect up-to 100% of the out-of-distribution data, improve inference accuracy by 15% for corrupted data, and ∼ 2% for in-distribution data.
Published: 2022
Full Text: View/download PDF

41. Electrical Coupling of Perpendicular Superparamagnetic Tunnel Junctions for Probabilistic Computing

Author: Nhat-Tan Phan, Lucile Soumah, Ahmed Sidi El Valli, Louis Hutin, Lorena Anghel, Ursula Ebels, Philippe Talatchian, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and ACM
Subjects: [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics
Published: 2022
Full Text: View/download PDF

42. Helicity dependent photoresistance measurement vs. beam-shift thermal gradient

Author: Haozhe Yang, Eva Schmoranzerová, Pyunghwa Jang, Jayshankar Nath, Thomas Guillet, Isabelle Joumard, Stéphane Auffret, Matthieu Jamet, Petr Němec, Gilles Gaudin, Ioan-Mihai Miron, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), CIC nanoGUNE, Faculty of Mathematics and Physics [Charles University of Praha], Charles University [Prague] (CU), and European Project: 638653,H2020,H2020-COMPET-2014,EUSPACE-AWE(2015)
Subjects: Multidisciplinary, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Physics and Astronomy, General Chemistry, General Biochemistry, Genetics and Molecular Biology
Abstract: Optical detection techniques are among the most powerful methods used to characterize spintronic phenomena. The spin orientation can affect the light polarization, which, by the reciprocal mechanism, can modify the spin density. Numerous recent experiments, report local changes in the spin density induced by a circularly polarized focused laser beam. These effects are typically probed electrically, by detecting the variations of the photoresistance or photocurrent associated to the reversal of the light helicity. Here we show that in general, when the light helicity is modified, the beam profile is slightly altered, and the barycenter of the laser spot is displaced. Consequently, the temperature gradients produced by the laser heating will be modulated, producing thermo-electric signals that alternate in phase with the light polarization. These unintended signals, having no connection with the electron spin, appear under the same experimental conditions and can be easily misinterpreted. We show how this contribution can be experimentally assessed and removed from the measured data. We find that even when the beam profile is optimized, this effect is large, and completely overshadows the spin related signals in all the materials and experimental conditions that we have tested.
Published: 2022
Full Text: View/download PDF

43. Improving DNN fault tolerance in semantic segmentation applications

Author: Stephane BurelT, Adrian EvansT, Lorena Anghel, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: Fault tolerant systems, Sensitivity, Hardware, [STAT.ML]Statistics [stat]/Machine Learning [stat.ML], Fault tolerance, Semantic segmentation, Fault detection, Very large scale integration
Abstract: International audience; Semantic segmentation of images is essential for autonomous driving and modern DNNs now achieve high accuracy. Automotive systems must comply with safety standards, requiring hardware fault detection. We present an analysis of the effect of faults using Google’s DeepLabV3+ network processing an industrial data-set. A new symptom-based fault detection algorithm is shown to detect >99% of critical faults with zero false positives and a compute overhead of 0.2%. Further, these faults can be masked, virtually eliminating all critical errors. To the authors’ knowledge this is the first fault tolerance study of a DNN semantic segmentation application.
Published: 2022
Full Text: View/download PDF

44. Non-local magnon transconductance in extended magnetic insulating films.\\Part II: two-fluid behavior

Author: Kohno, Ryuhei, Thiery, Nicolas, Clot, Eric, Schlitz, Richard, An, Kyongmo, Naletov, Vladimir V., Vila, Laurent, Beaulieu, Nathan, Youssef, Jamal Ben, Merbouche, Hugo, Cros, Vincent, Anane, Madjid, Hauet, Thomas, Demidov, Vladislav E., Demokritov, Sergej O., de Loubens, Gregoire, Klein, Olivier, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Departement Physik [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Westfälische Wilhelms-Universität Münster = University of Münster (WWU), Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, This work was partially supported by the French Grants ANR-18-CE24-0021 Maestro and ANR-21-CE24-0031 Harmony, the EU-project H2020-2020-FETOPEN k-NET-899646, the EU-project HORIZON-EIC-2021-PATHFINDEROPEN PALANTIRI-101046630. K.A. acknowledges support from the National Research Foundation of Korea (NRF) grant (No. 2021R1C1C201226911) funded by the Korean government (MSIT). This work was also supported in part by the Deutsche ForschungsGemeinschaft (Project number 416727653)., ANR-18-CE24-0021,MAESTRO,Excitation de magnons dans le régime fortement hors d'équilibre(2018), ANR-21-CE24-0031,Harmony,Hybridation entre Résonances Acoustique, Magnon et Photon dans le YIG.(2021), and European Project: 899646,H2020-FETOPEN-KNET
Subjects: Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], FOS: Physical sciences
Abstract: This review provides a comprehensive study of the spatial dispersion of propagating magnons, which are electrically emitted or absorbed inside extended YIG films by the spin transfer effects via a YIG$\vert$Pt interface. Our purpose is to provide a generic framework to describe magnon transconductance inside extended magnetic insulating films. We experimentally elucidate the relevant spectral contributions by studying the lateral decay of the magnon signal. While most of the injected magnons do not reach the collector, the propagating magnons may be split into two fluids: \textit{i)} a large portion of high-energy magnons carrying energy of about $k_B T_0$, where $T_0$ is the temperature of the lattice, with a characteristic decay length in the sub-micrometer range and \textit{ii)} a small portion of low-energy magnons, which are particles carrying energy of about $\hbar \omega_K$, where $\omega_K/(2 \pi)$ is the Kittel frequency, with a characteristic decay length in the micrometer range. Exploiting their different physical characteristics, the low-energy magnons may become the dominant fluid \textit{i)} at large spin transfer rate for the bias causing emission of magnons, \textit{ii)} at large distance from the emitter, \textit{iii)} at small film thickness or \textit{iv)} for reduced band mismatch between the YIG beneath the emitter and the bulk due to temperature change of the magnon bath. This broader picture amends part I \cite{kohno_SD}, which concentrates solely on the nonlinear transport properties of low-energy magnons.
Published: 2022

45. La détection des signaux radiofréquence et la génération des nombres aléatoires avec les jonctions tunnel magnétique perpendiculaire

Author: Sidi El Valli, Ahmed, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Université Grenoble Alpes [2020-....], Ursula Ebels, and Liliana Buda-Prejbeanu
Subjects: Perpendicular magnetic tunnel junctions, [PHYS.PHYS]Physics [physics]/Physics [physics], Dynamique de l’aimantation, Nano-Diodes à transfert de spin, Magnetization dynamics, Superparamagnetism, Trng, Jonctions tunnel magnétique perpendiculaire, Spin torque nanodiodes, Superparamagnétisme
Abstract: Nanoscale magnetic tunnel junctions (MTJ) are promising candidates for nonvolatile memories, magnetic sensors as well as for radiofrequency and unconventional computing applications. Transfer of spin angular momentum, from an injected spin polarized current, can drive three types of responses in these MTJs: (i) damped oscillations via an rf current, (ii) large angle auto-oscillations via a dc current, and (iii) switching between two stable states via a dc current. The first two excitations are of interest for applications within low power wireless sensor networks (WSNs) as well as for developing low power hardware of unconventional computing algorithms. The magnetization switching by contrast is exploited for nonvolatile memories where each state encodes a ‘0’ or ‘1’.In this thesis, we investigate the first response scheme for rf signal detection for low power wireless sensor nodes as well as the third response scheme for random number generation. Both studies make use of the same magnetic tunnel junctions that are characterized by a strong interfacial perpendicular magnetic anisotropy (iPMA) of the free layer and the pinned layer. Such perpendicular magnetic tunnel junctions (pMTJ) are currently seen by industrial partners as the most promising MTJ configuration for magnetic memory applications, because they can be made very small (down to 20nm diameter). Of interest for our studies here is that their internal fields are easily tunable through the variation of the device shape, because the ratio of the anisotropy energy due to IPMA and the demagnetization energy depends sensitively on the magnetic layer thickness and diameter. Slight variations in the free layer thickness (on the order of 0.2 nm) can lead to a drastic change of the magnetization orientation. For the devices used here, the free layer thickness was varied from t=1.4nm to 1.8nm. The first part of the thesis is a detailed analysis of the rf signal detection, to optimize the output DC voltage signal, as a function of magnetic layer thickness, the magnetic layer diameter as well as a function of the applied magnetic field orientation and the absence or presence of dc currents (passive vs. active active). It is found that, first, the passive rf detection signal of these pMTJs increases the more the iPMA compensates the demagnetizing energy. This can be achieved through a reduction of the device diameter, which additionally enhances the STT efficiency and reduces the effect from a serial resistance that will be present for MTJs co-integrated with CMOS. Secondly, in the active detection it is found that the detection frequency band can be tuned over several GHz through a dc current. This tuning is attributed to Joule heating and opens strategies for wide band frequency detection. The second part of the thesis demonstrates that a spin polarized DC current can bring these pMTJs into a superparamagnetic state at zero external magnetic field. Such bitstreams will be of interest for random number generation and unconventional computing schemes. Zero field operation will be facilitating the co-integration of these pMTJs with CMOS. The two parts of the thesis are accompanied by a thorough study of the static magneto-resistance loops as a function of applied field angle, DC current and temperature as well as by the modeling of the results based on solution of the Landau-Lifshitz-Gilbert equations.; Les jonctions tunnel magnétiques (MTJ) à l'échelle nanométrique sont des candidats prometteurs pour les mémoires non volatiles, les capteurs magnétiques ainsi que pour les applications de radiofréquence et de calcul non conventionnel. Le transfert du moment angulaire du spin, à partir d'un courant injecté polarisé en spin, peut entraîner trois types de réponses dans ces MTJ : (i) des oscillations amorties via un courant rf, (ii) des auto-oscillations à grand angle via un courant continu, et (iii) une commutation entre deux états stables via un courant continu. Les deux premières excitations sont intéressantes pour les applications dans les réseaux de capteurs sans fil (WSN) à faible puissance ainsi que pour le développement de matériel à faible puissance pour le calcul non conventionnels. La commutation de magnétisation, par contre, est exploitée pour les mémoires non-volatiles où chaque état code un '0' ou un '1'.Dans cette thèse, nous étudions le premier typede réponse pour la détection de signaux RF pour les nœuds de capteurs sans fil à faible puissance, ainsi que le troisième type de réponse pour la génération de nombres aléatoires. Les deux études utilisent les mêmes jonctions tunnel magnétiques qui sont caractérisées par une forte anisotropie magnétique perpendiculaire interfaciale (iPMA) de la couche libre et de la couche fixée. Ces jonctions tunnel magnétiques perpendiculaires (pMTJ) sont actuellement considérées par les partenaires industriels comme la configuration MTJ la plus prometteuse pour les applications de mémoire magnétique, car elles peuvent être fabriquées dans des dimensions très réduites (jusqu'à 20 nm de diamètre). L'intérêt pour nos études ici est que leurs champs internes sont facilement accordables par la variation de la forme du dispositif, car le rapport entre l'énergie d'anisotropie due à l'IPMA et l'énergie de démagnétisation dépend de manière sensible de l'épaisseur et du diamètre de la couche magnétique. De légères variations de l'épaisseur de la couche libre (de l'ordre de 0,2 nm) peuvent entraîner un changement radical de l'orientation de l'aimantation. Pour les dispositifs utilisés ici, l'épaisseur de la couche libre est varié de t=1.4nm à 1.8nm. La première partie de la thèse est une analyse détaillée de la détection du signal rf, pour optimiser le signal de tension continue de sortie, en fonction de l'épaisseur de la couche magnétique, du diamètre de la couche magnétique ainsi qu'en fonction de l'orientation du champ magnétique appliqué et de l'absence ou de la présence de courants continus (passif vs actif). On constate que, premièrement, le signal de détection rf passif de ces pMTJs augmente plus l'iPMA compense l'énergie de démagnétisation. Cela peut être obtenu par une réduction du diamètre du dispositif, ce qui améliore en outre l'efficacité du STT et réduit l'effet d'une résistance série qui sera présente pour les MTJ co-intégrés avec le CMOS. Deuxièmement, dans la détection active, on constate que la bande de fréquence de détection peut être accordée sur plusieurs GHz par un courant continu. Cet accord est attribué au chauffage par effet Joule et ouvre des perspectives pour la détection de fréquences à large bande. La deuxième partie de la thèse démontre qu'un courant continu polarisé en spin peut amener ces pMTJs dans un état superparamétique. De tels flux binaires seront intéressants pour la génération de nombres aléatoires et pour les calculs non conventionnels basés sur de tels générateurs de nombres aléatoires. Le fonctionnement à champ nul facilitera la co-intégration de ces pMTJs avec le CMOS. Les deux parties de la thèse sont accompagnées d'une étude approfondie des boucles de magnétorésistance statique en fonction de l'angle du champ appliqué, du courant continu et de la température ainsi que de la modélisation des résultats basée sur la résolution de l'équation de Landau-Lifshitz-Gilbert.Traduit avec www.DeepL.com/Translator (version gratuite)
Published: 2022

46. From Binary to Ternary Transition-Metal Nitrides: A Boost toward Nitrogen Magneto-Ionics

Author: Zhengwei Tan, Sofia Martins, Michael Escobar, Julius de Rojas, Fatima Ibrahim, Mairbek Chshiev, Alberto Quintana, Aitor Lopeandia, José L. Costa-Krämer, Enric Menéndez, Jordi Sort, Département de physique [Departament de Física, Universitat Autònoma de Barcelona], Universitat Autònoma de Barcelona (UAB), Department of Physics [Durham University], Durham University, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Institut de Ciència de Materials de Barcelona (ICMAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), ICN2 - Institut Catala de Nanociencia i Nanotecnologia (ICN2), IMN-Instituto de Micro y Nanotecnología (CNM-CSIC), Isaac Newton 8, PTM, 28760 Tres Cantos, Madrid, Spain, Institució Catalana de Recerca i Estudis Avançats (ICREA), European Research Council, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Generalitat de Catalunya, KU Leuven, Comunidad de Madrid, Ministerio de Economía y Competitividad (España), Rojas, Julius de, Chshiev, Mairbek, Quintana, Alberto, Menéndez, Enric, Sort, Jordi, Rojas, Julius de [0000-0002-1206-4744], Chshiev, Mairbek [0000-0001-9232-7622], Quintana, Alberto [0000-0002-9813-735X], Menéndez, Enric [0000-0003-3809-2863], and Sort, Jordi [0000-0003-1213-3639]
Subjects: Magnetoelectricity, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Ion diffusion, General Materials Science, Voltage control of magnetism (VCM), Magneto-ionics, Transition metal nitride
Abstract: Magneto-ionics is an emerging actuation mechanism to control the magnetic properties of materials via voltage-driven ion motion. This effect largely relies on the strength and penetration of the induced electric field into the target material, the amount of generated ion transport pathways, and the ionic mobility inside the magnetic media. Optimizing all these factors in a simple way is a huge challenge, although highly desirable for technological applications. Here, we demonstrate that the introduction of suitable transition-metal elements to binary nitride compounds can drastically boost magneto-ionics. More specifically, we show that the attained magneto-ionic effects in CoN films (i.e., saturation magnetization, toggling speeds, and cyclability) can be drastically enhanced through 10% substitution of Co by Mn in the thin-film composition. Incorporation of Mn leads to transformation from nanocrystalline into amorphous-like structures, as well as from metallic to semiconducting behaviors, resulting in an increase of N-ion transport channels. Ab initio calculations reveal a lower energy barrier for CoMn-N compared to Co-N that provides a fundamental understanding of the crucial role of Mn addition in the voltage-driven magnetic effects. These results constitute an important step forward toward enhanced voltage control of magnetism via electric field-driven ion motion., Financial support by the European Research Council (MAGIC-SWITCH 2019-Proof of Concept Grant, agreement no 875018; REMINDS 2021-ERC-Advanced Grant, agreement no 101054687), the European Union’s Horizon 2020 research and innovation program (European Training Network, ETN/ITN Marie Skłodowska-Curie grant no 861145; and Integrated Infrastructure, RADIATE, grant no 824096), the Spanish Government (PID2020-116844RB-C21 and PDC2021-121276-C31), the Generalitat de Catalunya (2017-SGR-292), and the KU Leuven (BOF program) is acknowledged. We acknowledge the technical support from the MiNa Laboratory at IMN in Madrid, who received funding from the CM (project S2018/NMT-4291 TEC2SPACE), MINECO (project CSIC13-4E-1794), and EU (FEDER, FSE). A.Q. acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities through the “Severo Ochoa” Programme for Centers of Excellence in R&D (FUNFUTURE CEX2019-000917-S) and the “Juan de la Cierva─Formación” contract (FJC2019-039780-I). J.S. thanks the Spanish “Fábrica Nacional de Moneda y Timbre” (FNMT) for fruitful discussions. E.M. is a Serra Húnter Fellow., With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).
Published: 2022
Full Text: View/download PDF

47. Spin Orbit Torque-based Crossbar Array for Error Resilient Binary Convolutional Neural Network

Author: Kamal Danouchi, Guillaume Prenat, Lorena Anghel, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: [SPI]Engineering Sciences [physics], [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics
Abstract: International audience; Convolutional Neural Network (CNN) is one of the most important Deep Neural Networks (DNN) classes that helps solving many tasks related to image recognition and computer vision. Their classical implementations by using conventional CMOS technologies and digital design techniques are still considered very energy-consuming. Floating point CNN relies primarily on MAC (Multiply and ACcumulate) operation. Recently, cost-effective Bite-wise CNN based on XNOR and bit-counting operations have been considered as a possible hardware implementation candidate. However, the Von-Neumann bottleneck due to intensive data fetching between memory and the computing core limits their scalability on hardware. XNOR-BITCOUNT operations can be easily implemented by using In Memory Computing (IMC) paradigms executed on a memristive crossbar array. Among emerging memristive devices, the Spin-Orbit Torque Magnetic Random Access Memory (SOT-MRAM) offers the possibility to have a higher ON resistance that allows reducing the reading current, since all the crossbar array is read in parallel. This could contribute to a further reduction of energy consumption, paving the way for much bigger crossbar designs. This study presents a crossbar architecture based on SOT-MRAM with very low energy consumption; we study the impact of process variability on the synaptic weights and perform Monte-Carlo simulations of the overall crossbar array to evaluate the error rate. Simulation results show that this implementation has lower energy consumption with respect to other memristive solutions with 65.89 fJ per read operation. The design is also quite robust to process variations, with very low reading inaccuracies up to 10 %.
Published: 2022

48. Spin Torque Efficiency Modulation in a Double-Barrier Magnetic Tunnel Junction with a Read/Write Mode Control Layer

Author: Jyotirmoy Chatterjee, Laurent Vila, Paulo Coelho, A. Chavent, Liliana D. Buda-Prejbeanu, Stéphane Auffret, Claire Baraduc, Ioan Lucian Prejbeanu, Nikita Strelkov, Bernard Dieny, Ricardo C. Sousa, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and Lomonosov Moscow State University (MSU)
Subjects: perpendicular magnetic anisotropy (PMA), Materials science, 02 engineering and technology, Double barrier, 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, Computer Science::Hardware Architecture, [SPI]Engineering Sciences [physics], 0103 physical sciences, Materials Chemistry, Electrochemistry, Torque, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Spin-½, 010302 applied physics, Condensed matter physics, 021001 nanoscience & nanotechnology, [SPI.TRON]Engineering Sciences [physics]/Electronics, Electronic, Optical and Magnetic Materials, Tunnel magnetoresistance, write efficiency, Modulation, double barrier, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Mode control, spin torque modulation, 0210 nano-technology, thermal stability factor, Layer (electronics), spin transfer torque (STT)
Abstract: International audience; To improve the read/write margin in perpendicular spin transfer torque magnetic random access memory (STT-MRAM), a concept of the double-magnetic tunnel junction (MTJ) MRAM cell is proposed in which the STT efficiency can be changed between read and write modes. In conventional double-MTJ stacks, the storage layer magnetization is submitted to two additive STT contributions, one from the reference layer below the bottom tunnel barrier and the other from an additional polarizing layer above the top tunnel barrier. In the proposed stack, the magnetization of the top polarizing layer can be switched between the read and write mode by domain wall propagation or spin orbit torque. This allows us to maximize the STT on the storage layer during write and minimize it during read. The associated advantages are a lower write current, reduced read disturb, maximal magnetoresistance amplitude during read, and faster read thanks to larger read current. We report here the experimental demonstration of this concept on perpendicular double-MTJ stacks.
Published: 2021
Full Text: View/download PDF

49. A fast, energy efficient and tunable magnetic tunnel junction based bitstream generator for stochastic computing

Author: Etienne Becle, Guillaume Prenat, Philippe Talatchian, Lorena Anghel, Ioan-Lucian Prejbeanu, SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)
Subjects: Hardware and Architecture, Electrical and Electronic Engineering, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics
Abstract: International audience; This paper presents a full hardware implementation of a magnetic tunnel junction based stochastic tunable bitstream generator. It provides highly accurate control of the switching probability, while showing important robustness to process and temperature variations. We propose a new architecture of sensing scheme based on the pre-charged sense amplifier approach that uses an asynchronous digital module to control the internal signals of the sense amplifier with the purpose of improving the reliability against the timing hazards and reducing the power consumption by detecting the end of the reading to stop the required static currents. The circuit also features a digital feedback loop that analyzes the output bitstream and adapt the current in such a way that the bitstream encodes precisely the required probability. This circuit features an important bit generation rate at a low energy cost. Based on an exhaustive characterization of the circuit, we provide a behavioral description in Verilog, with timing and power files to be integrated as a standard cell in the digital design flow for application level evaluation of the performance. Thus, we also provide a design and evaluation flow from device to digital level of abstraction.
Published: 2022
Full Text: View/download PDF

50. Spin-orbit torque switching of magnetic tunnel junctions for memory application

Author: Viola Krizakova, Manu Perumkunnil, Sébastien Couet, Pietro Gambardella, Kevin Garello, Departement Physik [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), IMEC (IMEC), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Department of Materials [ETH Zürich] (D-MATL), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), and Financial support by the Swiss National Science Foundation (Grant No. 200020_200465), by IMEC’s industrial affiliation program on MRAM device, and by the ECSEL joint undertaking program (Grant No 876925 – Project Andante).
Subjects: Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), FOS: Physical sciences, Applied Physics (physics.app-ph), Physics - Applied Physics, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Condensed Matter Physics, Electronic, Optical and Magnetic Materials
Abstract: International audience; Spin-orbit torques (SOT) provide a versatile tool to manipulate the magnetization of diverse classes of materials and devices using electric currents, leading to novel spintronic memory and computing approaches. In parallel to spin transfer torques (STT), which have emerged as a leading non-volatile memory technology, SOT broaden the scope of current-induced magnetic switching to applications that run close to the clock speed of the central processing unit and unconventional computing architectures. In this paper, we review the fundamental characteristics of SOT and their use to switch magnetic tunnel junction (MTJ) devices, the elementary unit of the magnetoresistive random access memory (MRAM). In the first part, we illustrate the physical mechanisms that drive the SOT and magnetization reversal in nanoscale structures. In the second part, we focus on the SOT-MTJ cell. We discuss the anatomy of the MTJ in terms of materials and stack development, summarize the figures of merit for SOT switching, review the field-free operation of perpendicularly magnetized MTJs, and present options to combine SOT, STT and voltage-gate assisted switching. In the third part, we consider SOT-MRAMs in the perspective of circuit integration processes, introducing considerations on scaling and performance, as well as macro-design architectures. We thus bridge the fundamental description of SOT-driven magnetization dynamics with an application-oriented perspective, including device and system-level considerations, goals, and challenges.
Published: 2022
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Publication Type

Journal

Database

Publisher

749 results on '"SPINtronique et TEchnologie des Composants (SPINTEC)"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources