Author: "Jean-Marie George" - Searchworks@Jio Institute Digital Library Search Results

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58 results on '"Jean-Marie George"'

1. Theory of spin and orbital charge conversion at the surface states of Bi_{1−x}Sb_{x} topological insulator

Author: Armando Pezo, Jean-Marie George, and Henri Jaffrès
Subjects: Physics, QC1-999
Abstract: Topological insulators are quantum materials involving time-reversal protected surface states making them appealing candidates for the design of the next generation of highly efficient spintronic devices. The very recent observation of large transient spin-charge conversion and subsequent powerful THz emission from Co/Bi_{1−x}Sb_{x} bilayers clearly demonstrates such potentiality and feasibility for the near future. Among the exotic properties appearing in and at the surface of such quantum materials, spin-momentum locking and Rashba-Edelstein effects remain as key ingredients to effectively convert the spin degree of freedom into a charge or a voltage signal. In this work, we extend our analyses to the quantification of orbital momentum-locking and related orbital charge conversion effects in Bi_{.85}Sb_{.15} via orbital Rashba-Edelstein effects. In that sense, we will provide some clear theoretical and numerical insights implemented by multiorbital and slab tight-binding methods to clarify our recent experimental results obtained by THz spectroscopy in the time domain.
Published: 2024
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2. Electrical spin injection and detection in molybdenum disulfide multilayer channel

Author: Shiheng Liang, Huaiwen Yang, Pierre Renucci, Bingshan Tao, Piotr Laczkowski, Stefan Mc-Murtry, Gang Wang, Xavier Marie, Jean-Marie George, Sébastien Petit-Watelot, Abdelhak Djeffal, Stéphane Mangin, Henri Jaffrès, and Yuan Lu
Subjects: Science
Abstract: MoS2 is a promising two-dimensional candidate for opto-electronic and spintronic applications. Here, the authors report electrical spin injection and detection in a few-layered MoS2 channel, demonstrating that the spin diffusion length is at least 235 nm in MoS2conduction band.
Published: 2017
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3. Enhancement of spin-orbit torques in ferromagnetic layer via orbital Hall effect (Conference Presentation)

Author: Sachin Krishnia, Vincent Cros, Sophie Collin, Jean-Marie George, and Henri-Yves Jaffrès
Published: 2022
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4. Surface states mediated spin-to-charge conversion in Bi1-xSbx/Co and Bi2SnTe4/Co topological insulators probed by THz emission spectroscopy. (Conference Presentation)

Author: Enzo Rongione, Laëtitia Baringthon, Sotirios Fragkos, Jacques Hawecker, Thi-Huong Dang, Evangelia Xenogiannopoulou, Polychronis Tsipas, Patrick Le Fèvre, Nicolas Reyren, Gilles Patriarche, Aristide Lemaître, Athanasios Dimoulas, Romain Lebrun, Jean-Marie George, Sukhdeep Dhillon, and Henri Jaffrès
Published: 2022
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5. Topological surface states in ultrathin Bi1−xSbx layers

Author: Laëtitia Baringthon, Thi Huong Dang, Henri Jaffrès, Nicolas Reyren, Jean-Marie George, Martina Morassi, Gilles Patriarche, Aristide Lemaitre, François Bertran, and Patrick Le Fèvre
Subjects: Physics and Astronomy (miscellaneous), General Materials Science
Published: 2022
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6. Origin of the anomalous Hall effect at the magnetic insulator/heavy metals interface

Author: Sajid Husain, Nicholas Figueiredo-Prestes, Olivier Fayet, Sophie Collin, Florian Godel, Eric Jacquet, Nicolas Reyren, Henri Jaffrès, and Jean-Marie George
Subjects: Physics and Astronomy (miscellaneous)
Abstract: Ferrimagnetic insulators (FIMIs) are considered to be promising candidates in spin–orbit torque (SOT) devices due to their ability to propagate a spin current by magnons without Ohmic losses owing to the absence of electronic scattering. Moreover, any electrical current shunt is avoided in magnetic insulating materials. On the other hand, SOT-induced magnetization switching is generally measured through the anomalous Hall effect (AHE) in FIMI/heavy metal (HM) systems. However, the origin of AHE in FIMI/HM remains elusive since charges flow only in the HM. Here, we experimentally demonstrate that the AHE has the same origin as the spin Hall magnetoresistance (SMR). To this end, we have studied two bilayer heterostructures, Tm3Fe5O12(TmIG)/W and TmIG/Pt, where we ensure opposite spin Hall effect (SHE) signs for two heavy metals (W and Pt). The magnitudes of AHE and SMR are found to be larger for TmIG/W than TmIG/Pt. We have also evidenced the identical polarity of AHE hysteresis in both systems revealing a square dependency on the spin Hall angle whereas the current-induced magnetization switching polarity in TmIG/W is opposite to that of TmIG/Pt as expected for opposite spin Hall angle signs. Our results establish that the AHE and the spin-Hall magnetoresistance in TmIG insulating ferromagnets and heavy metal bilayers originate from the same mechanism.
Published: 2023
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7. Spin-Orbit Currents, Spin-Transfer Torque and Anomalous Tunneling in III–V Heterostructures Probed by Advanced 30- and 40-Bands ${k}\cdot{p}$ Tunneling Methods

Author: Henri Jaffrès, T. H. Dang, Jean-Marie George, Henri-Jean M. Drouhin, Duy Quang To, Viatcheslav Safarov, Hoai Nguyen, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, and THALES [France]-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], 010302 applied physics, Physics, [PHYS.PHYS]Physics [physics]/Physics [physics], Magnetoresistance, Condensed matter physics, Spin-transfer torque, Heterojunction, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 01 natural sciences, Electronic, Optical and Magnetic Materials, Magnetization, Transverse plane, Hall effect, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Boundary value problem, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Electrical and Electronic Engineering, Quantum tunnelling
Abstract: On the basis of tunneling magnetoresistance (TMR) spin-transfer torque (STT) experiments in (Ga,Mn)As/GaAs/(Ga,Mn)As submicronic magnetic tunnel junctions, we have analyzed the anatomy of the spin-current profiles within the heterostructures, location of strong spin–orbit interactions. Beyond the TMR, our robust 30- and 40-band $k\cdot p$ numerical methods reveal the strong peculiarity of the spin-currents in the antiparallel state with the evidence of a tunneling anomalous Hall effect. Using the boundary conditions corresponding to heavy-hole (HH)-to-light-hole (LH) mixing of the relevant $\text{C}_{2v}$ symmetry at III–V interfaces of the junctions, we demonstrate that the efficiency of the transverse spin-current necessary to STT is surprisingly enhanced by the HH-to-LH mixing taking benefit of the lighter mass of the LH state.
Published: 2019
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8. Revealing large field-like torque in Pt / Co / Al / Pt magnetic multilayers

Author: Vincent Cros, Sophie Collin, Fernando Ajejas, Nicolas Reyren, Albert Fert, Henri Jaffrès, Yanis Sassi, Jean-Marie George, and Sachin Krishnia
Subjects: Metal, Magnetization, Materials science, Ferromagnetism, Condensed matter physics, Field (physics), visual_art, Point reflection, Spin Hall effect, visual_art.visual_art_medium, Torque, Condensed Matter::Strongly Correlated Electrons, Rashba effect
Abstract: Spin-orbit torques (SOTs) allow controlling the magnetization of diverse classes of magnetic multilayers and devices. The mechanism utilizes spin-orbit interactions such as spin Hall effect in heavy metals and/or Rashba effect at ferromagnetic/heavy-metal interface with broken inversion symmetry. The SOTs have damping-like (HDL) and field-like (HFL) effective field components. In this talk, we will present the mechanism of spin-transport in ultrathin magnetic multilayer whose thicknesses span across the characteristic spin-dephasing length, and how it results in HDL and HFL nearby the crossing point of this specific length. To this aim, we have quantified SOTs in a series of samples Pt 8|Co x|Al 1.4|Pt 3 with x = 0.55, 0.7, 0.9, 1.2, 1.4 nm. Our experiments demonstrate the presence of very large field-like torque arising from Co|Al interface for Co thickness smaller than spin-dephasing length. The results suggest the contribution of additional mechanisms of spin-current generation.
Published: 2021
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9. Large Perpendicular Magnetic Anisotropy in Ta/CoFeB/MgO on Full-Coverage Monolayer MoS

Author: Ziqi, Zhou, Paul, Marcon, Xavier, Devaux, Philippe, Pigeat, Alexandre, Bouché, Sylvie, Migot, Abdallah, Jaafar, Rémi, Arras, Michel, Vergnat, Lei, Ren, Hans, Tornatzky, Cedric, Robert, Xavier, Marie, Jean-Marie, George, Henri-Yves, Jaffrès, Mathieu, Stoffel, Hervé, Rinnert, Zhongming, Wei, Pierre, Renucci, Lionel, Calmels, and Yuan, Lu
Abstract: A perpendicularly magnetized spin injector with a high Curie temperature is a prerequisite for developing spin optoelectronic devices on two-dimensional (2D) materials working at room temperature (RT) with zero applied magnetic field. Here, we report the growth of Ta/CoFeB/MgO structures with large perpendicular magnetic anisotropy (PMA) on full-coverage monolayer (ML) molybdenum disulfide (MoS
Published: 2021

10. Spin Injection Efficiency at Metallic Interfaces Probed by THz Emission Spectroscopy

Author: Yannis Laplace, Jérôme Tignon, Sukhdeep Dhillon, Romain Grasset, Sophie Collin, Henri Jaffrès, James Boust, Luca Perfetti, Henri-Jean Drouhin, E. Rongione, Jingwei Dong, Juliette Mangeney, Jean-Marie George, Thi Huong Dang, J. Hawecker, Nano-THz, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Technische Universität Dortmund [Dortmund] (TU), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire de physique de l'ENS - ENS Paris (LPENS), Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Sorbonne Université (SU)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Sorbonne Université (SU)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Centre National de la Recherche Scientifique (CNRS)-THALES, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPC)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPC), Centre National de la Recherche Scientifique (CNRS)-THALES [France], Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'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)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, and ANR-16-CE24-0017,TOP-RISE,Isolant topologique et etats d'interfaces Rashba pour l'électronique de spin(2016)
Subjects: Materials science, Terahertz radiation, ultrafast, THz emitters, Physics::Optics, FOS: Physical sciences, 02 engineering and technology, spin conductance, 010402 general chemistry, 01 natural sciences, symbols.namesake, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), broad-bandwidth, inverse spin Hall effect, Emission spectrum, Spin (physics), spintronics, [PHYS]Physics [physics], Condensed Matter - Materials Science, Spintronics, Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, Ferromagnetic resonance, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, symbols, Spin Hall effect, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology, Hamiltonian (quantum mechanics), Ultrashort pulse
Abstract: International audience; Terahertz (THz) spin-to-charge conversion has become an increasingly important process for THz pulse generation and as a tool to probe ultrafast spin interactions at magnetic interfaces. However, its relation to traditional, steady state, ferromagnetic resonance techniques is poorly understood. Here we investigate nanometric trilayers of Co/X/Pt (X=Ti, Au or Au0:85W0:15) as a function of the 'X' layer thickness, where THz emission generated by the inverse spin Hall effect is compared to the Gilbert damping of the ferromagnetic resonance. Through the insertion of the 'X' layer we show that the ultrafast spin current injected in the non-magnetic layer defines a direct spin conductance, whereas the Gilbert damping leads to an effective spin mixing-conductance of the trilayer. Importantly, we show that these two parameters are connected to each other and that spinmemory losses can be modeled via an effective Hamiltonian with Rashba fields. This work highlights that magneto-circuits concepts can be successfully extended to ultrafast spintronic devices, as well as enhancing the understanding of spin-to-charge conversion processes through the complementarity between ultrafast THz spectroscopy and steady state techniques.
Published: 2021
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11. Ultrafast spin-charge interconversion in Rashba states probed by time-domain THz spectroscopy

Author: Manuel Bibes, Albert Fert, Florian Godel, Kirill D. Belashchenko, Diogo C. Vaz, Juliette Mangeney, Sukhdeep Dhillon, Luis Moreno, Juan-Carlos Rojas-Sánchez, Jérôme Tignon, Jean-Philippe Attané, Daniel Dolfi, Jean-Marie George, T. H. Dang, P. Bortolotti, Hanond Nong, Giovanni Baez Flores, Sophie Collin, Henri Jaffrès, J. Hawecker, Romain Lebrun, Laurent Vila, Abdelmadjid Anane, Paul Noël, Enzo Faycal Rongione, and Pierre Seneor
Subjects: Materials science, Condensed matter physics, Terahertz radiation, Topological insulator, Spin Hall effect, Physics::Optics, Condensed Matter::Strongly Correlated Electrons, Emission spectrum, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Spin (physics), Fermi gas, Ultrashort pulse, Surface states
Abstract: Terahertz (THz) emission spectroscopy in spin systems has become a very powerful method to generate THz radiation and to investigate the properties of Rashba or Topological Insulator surface states. The THz emission can be generated in heavy metallic or in more general Rashba systems. In 3d/5d transient metal bilayers THz emission in via the Inverse Spin Hall effect. Beyond heavy metal structures, Rashba states are strong candidates for THz-spintronics owing to their high spin to charge conversion properties. Here we present 2D electron gas with strong Rashba spin-orbit coupling and demonstrate THz emission via the Inverse Edelstein Effect.
Published: 2020
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12. Germanium: a semiconducting platform for spin-orbitronics

Author: Franco Ciccacci, C. Vergnaud, Adele Marchionni, Alain Marty, Mair Chshiev, Quentin Barbedienne, Matthieu Jamet, Marco Finazzi, Paolo Biagioni, Federico Bottegoni, Nicolas Reyren, T. Guillet, Jean-Marie George, Carlo Zucchetti, Aurélien Masseboeuf, Giovanni Isella, Henri Jaffrès, Albert Fert, Ali Hallal, Hanako Okuno, SPINtronique et TEchnologie des Composants (SPINTEC), 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 National de la Recherche Scientifique (CNRS), Dipartimento di Fisica [Politecnico Milano], Politecnico di Milano [Milan] (POLIMI), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes (UGA)-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), 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), Dipartimento di Fisica [Politecnico Milano] (POLIMI), and THALES [France]-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010302 applied physics, Materials science, Magnetoresistance, Spintronics, business.industry, Silicon on insulator, chemistry.chemical_element, Germanium, Substrate (electronics), 7. Clean energy, 01 natural sciences, chemistry, Topological insulator, Electric field, 0103 physical sciences, Optoelectronics, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, business, ComputingMilieux_MISCELLANEOUS, Rashba effect
Abstract: Germanium is a very good candidate to host a versatile spintronics platform thanks to its unique spin and optical properties. Recently we focused on two approaches in order to tune the spin-orbit interaction (SOI) in this Ge-based platform. The first one relies on growing high quality epitaxial topological insulators (TIs) on a Ge (111) substrate, we developed an original method to probe the spin-to-charge conversion at the TI/Ge(111) interface by taking advantage of the Ge optical properties. The latter approach is to exploit the intrinsic SOI of Ge (111). By investigating the electrical properties of a thin Ge(111), we found a large unidirectional Rashba magnetoresistance, which we ascribe to the interplay between the externally applied magnetic field and the current-induced pseudo-magnetic field applied in the spin-splitted subsurface states of Ge (111). Both studies open a door towards spin manipulation with electric fields in an all-semiconductor technology platform.
Published: 2020
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13. Electrical Initialization of Electron and Nuclear Spins in a Single Quantum Dot at Zero Magnetic Field

Author: Xavier Marie, Mathieu Stoffel, Bernhard Urbaszek, Zhanguo Wang, Xiufeng Han, Xavier Devaux, Andrea Balocchi, Hélène Carrère, Pierre Renucci, Jean-Marie George, Yuan Lu, Delphine Lagarde, Stéphane Mangin, Abdelhak Djeffal, Shiheng Liang, Bo Xu, Bingshan Tao, Thierry Amand, Fabian Cadiz, Henri Jaffrès, Michel Hehn, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Centre National de la Recherche Scientifique (CNRS)-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 (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Institut Jean Lamour (IJL), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences [Beijing] (CAS), Compiler Optimization and Run-time Systems (CORSE), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire d'Informatique de Grenoble (LIG), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Unité mixte de physique CNRS/Thalès (UMP CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA), Bejing national laboratory of condensed matter Physics, Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences (KLSMS), Institute of Semiconductors, Chinese Academy of Sciences (IOS), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), 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)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institute of semiconductors [Chinese Academy of Sciences - Beijing] (IOS), Chinese Academy of Science (CAS)-Chinese Academy of Science (CAS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Beijing National Laboratory for Condensed Matter Physics and Institute of Physics (IoP/CAS), Chinese Academy of Sciences [Changchun Branch] (CAS), IMPACT N4S, ANR-15-IDEX-0004,LUE,Isite LUE(2015), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Key Laboratory of Semiconductor Materials Science (LSMS), Chinese Academy of Sciences [Beijing] (CAS)-Chinese Academy of Sciences [Beijing] (CAS), and THALES [France]-Centre National de la Recherche Scientifique (CNRS)
Subjects: FOS: Physical sciences, Bioengineering, 02 engineering and technology, 01 natural sciences, Spinled, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, electrical spin injection, General Materials Science, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 010306 general physics, Spin (physics), Hyperfine structure, ComputingMilieux_MISCELLANEOUS, Circular polarization, spintronics, Physics, Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Condensed matter physics, Spin polarization, Spintronics, Mechanical Engineering, Materials Science (cond-mat.mtrl-sci), General Chemistry, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Magnetic field, Quantum dot, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Trion, 0210 nano-technology
Abstract: The emission of circularly polarized light from a single quantum dot relies on the injection of carriers with well-defined spin polarization. Here we demonstrate single dot electroluminescence (EL) with a circular polarization degree up to 35% at zero applied magnetic field. The injection of spin polarized electrons is achieved by combining ultrathin CoFeB electrodes on top of a spin-LED device with p-type InGaAs quantum dots in the active region. We measure an Overhauser shift of several $\mu$eV at zero magnetic field for the positively charged exciton (trion X$^+$) EL emission, which changes sign as we reverse the injected electron spin orientation. This is a signature of dynamic polarization of the nuclear spins in the quantum dot induced by the hyperfine interaction with the electrically injected electron spin. This study paves the way for electrical control of nuclear spin polarization in a single quantum dot without any external magnetic field., Comment: initial version, final version to appear in ACS Nano Letters
Published: 2018
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14. Atomic-scale understanding of high thermal stability of the Mo/CoFeB/MgO spin injector for spin-injection in remanence

Author: Abdelhak Djeffal, Xavier Devaux, Xavier Marie, Yuan Lu, Stéphane Mangin, Jean-Marie George, Philippe Barate, Zhanguo Wang, Xiufeng Han, Henri Jaffrès, Pierre Renucci, Shiheng Liang, Bo Xu, Bingshan Tao, Frougier Julien, Michel Hehn, Institut Jean Lamour (IJL), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thalès (UMP CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), University of Science and Technology of China [Hefei] (USTC), Institut National des Sciences Appliquées (INSA), University of Chinese Academy of Sciences [Beijing] (UCAS), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), IMPACT N4S, Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), 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)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)
Subjects: 010302 applied physics, Materials science, Annealing (metallurgy), Analytical chemistry, 02 engineering and technology, Electroluminescence, 021001 nanoscience & nanotechnology, 01 natural sciences, law.invention, Magnetic field, Remanence, law, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, Thermal stability, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 0210 nano-technology, Spectroscopy, ComputingMilieux_MISCELLANEOUS, Quantum tunnelling, Light-emitting diode
Abstract: International audience; Remanent spin injection into a spin light emitting diode (spin-LED) at zero magnetic field is a prerequisite for future application of spin optoelectronics. Here, we demonstrate the remanent spin injection into GaAs based LEDs with a thermally stable Mo/CoFeB/MgO spin injector. A systematic study of magnetic properties, polarization-resolved electroluminescence (EL) and atomic-scale interfacial structures has been performed in comparison with the Ta/CoFeB/MgO spin injector. The perpendicular magnetic an-isotropy (PMA) of the Mo/CoFeB/MgO injector shows more advanced thermal stability than that of the Ta/CoFeB/MgO injector and robust PMA can be maintained up to 400 °C annealing. The remanent circular polarization (P C) of EL from the Mo capped spin-LED reaches a maximum value of 10% after 300 °C annealing, and even remains at 4% after 400 °C annealing. In contrast, the Ta capped spin-LED almost completely loses the remanent P C under 400 °C annealing. Combined advanced electron microscopy and spectroscopy studies reveal that a large amount of Ta diffuses into the MgO tunneling barrier through the CoFeB layer after 400 °C annealing. However, the diffusion of Mo into CoFeB is limited and never reaches the MgO barrier. These findings afford a comprehensive perspective to use the highly thermally stable Mo/CoFeB/MgO spin injector for efficient electrical spin injection in remanence.
Published: 2018
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15. Direct measurement of the two components of the spin-orbit-torque (SOT) in NiFe/Pt bilayers by an AMR-based Wheatstone bridge (Conference Presentation)

Author: David Vissiere, Jean-Marie George, Augustin Jouy, Sophie Collin, Malik Mansour, Henri Jaffrès, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and SYSNAV
Subjects: Physics, Wheatstone bridge, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Condensed matter physics, Field (physics), 01 natural sciences, Symmetry (physics), law.invention, 010309 optics, Amplitude, Ferromagnetism, law, 0103 physical sciences, Torque, Angular resolution (graph drawing), 010303 astronomy & astrophysics, Current density, ComputingMilieux_MISCELLANEOUS
Abstract: We will present an alternative method for spin-torque measurements and spin-currents interface characterization in a pure DC configuration measurement. It consists in consists in developing an home-made NiFe-based 4-branches AMR Wheatstone bridge sensors with a specific design allowing opposite spin-current flow in each of the opposite bridge arms. We have experimented the method on well-characterized NiFe(10nm)/Pt as well as NiFe(10nm)/Pt/Au:W systems reliable for spin-torque and THz emission. If the field-like torque and Oersted field simply manifest by a shift in the characteristic transfer of the sensors, the antidamping torque is generally more subtle to evidence. We will present the characteristics of the developed sensors in terms of sensitivity and angular resolution below 0.05°. We will present in details the specific method and protocol measurements in the out-of-plane field geometry allowing from specific symmetry considerations the extraction of the antidamping component, linear in the current density and with a magnitude of 10 G for a current density of 3x1011 A.cm-2. The amplitude of the spin-torque measured is in close agreement with the expectations [7] and with models including spin-memory loss effects like recently revealed by spin-pumping FMR experiments [4]. References: [1] I.M. Miron et al., Nat Mater. 9, 230 [2010]. [2] Frances Hellman et al., Rev. Mod. Phys. 89, 025006 [2010]. [3] J.-C. Rojas-Sanchez et al., Phys. Rev. Lett. 112, 106602 [2014]. [4] A. J. Berger et al., Phys. Rev. B 98, 024402 [2018]. [5] L. Liu et al., Phys. Rev. Lett. 106, 036601 [2011]. [6] K. Garello et al., Nat.Nano. 8, 587 (2013)[7] T. Seifert et al., Nat. Phot. 10, pages 483–488 [2016].
Published: 2019
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16. Co - Fe - B/MgO/Ge Spin Photodiode Operating at Telecommunication Wavelength with Zero Applied Magnetic Field

Author: Sylvie Migot, Xavier Marie, Fabian Cadiz, Henri Jaffrès, Abdelhak Djeffal, Xue Gao, Mathieu Stoffel, Yuan Lu, Stéphane Mangin, Jean-Marie George, Hervé Rinnert, Delphine Lagarde, Pierre Renucci, and Xavier Devaux
Subjects: Photocurrent, Materials science, Spin polarization, Spintronics, business.industry, General Physics and Astronomy, Heterojunction, 02 engineering and technology, Atmospheric temperature range, 021001 nanoscience & nanotechnology, 01 natural sciences, Photodiode, law.invention, Magnetic anisotropy, law, 0103 physical sciences, 010306 general physics, 0210 nano-technology, Telecommunications, business, Molecular beam epitaxy
Abstract: We report on the growth and study of Co-Fe-B/MgO/Ge(001) spin photodiode by using a combination of both molecular beam epitaxy (MBE) and sputtering methods. An epitaxial growth of MgO on Ge in MBE is achieved by the deposition of MgO at room temperature (RT) followed by a post-growth anneal-ing at 300 °C. The spin detector, which consists of 1.1-nm ultrathin Co-Fe-B layer capped with 5-nm Ta is subsequently grown by sputtering at RT. After a post-growth annealing of the whole structure at 250 °C, we obtain clear evidence of a strong perpendicular magnetic anisotropy in the temperature range 10-300 K. Co-Fe-B/MgO/Ge(001) heterojunctions are then processed into spin photodiodes demonstrating at zero magnetic field a photocurrent helicity asymmetry of about 0.9% at 9 K and 0.1% at RT at the telecommunication wavelength of 1310 nm. The demonstration of a spin photodiode working at a telecommunication wavelength with zero applied magnetic field is of great interest for future applications of the optical transport of spin information.
Published: 2018
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17. Toward efficient spin/charge conversion using topological insulator surface (Conference Presentation)

Author: Albert Fert, Céline Vergnaud, Patrick Lefèvre, Henri Jaffrès, Alain Marty, Nicolas Reyren, Laurent Vila, François Bertran, Paul Noël, A. Taleb-Ibrahimi, Q. Barbedienne, Jean-Marie George, Aristide Lemaître, Julien Varignon, 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)-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), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies (C2N), and Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Surface (mathematics), Condensed matter physics, Topological insulator, Charge (physics), [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Spin-½
Abstract: International audience
Published: 2018
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18. Spin diffusion transport in vertical metal/silicon/metal heterostructure (Conference Presentation)

Author: Michel Hehn, Zhi Liu, S. Suire, P. Laczkowski, Xiufeng Han, Abdelhak Djeffal, Xavier Devaux, T. H. Dang, Philippe Schieffer, Jianying Qin, Henri Jaffrès, Mathieu Stoffel, Sylvie Migot, Jean-Marie George, Jean-Christophe Le Breton, Juan Carlos Rojas Sanchez, Carolina Cerqueira, Stéphane Mangin, Sebastien Petit Watelot, Yuan Lu, Abdelmadjid Anane, and Buwen Chen
Subjects: Materials science, Silicon, business.industry, media_common.quotation_subject, chemistry.chemical_element, Heterojunction, Metal, Presentation, chemistry, visual_art, visual_art.visual_art_medium, Spin diffusion, Optoelectronics, business, media_common
Published: 2018
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19. Spin-Hall effects and unconventional anomalous Hall effects in transition-metal based metallic spintronic multilayers for THz emission (Conference Presentation)

Author: Laurent Divay, Jean-Marie George, T. H. Dang, Hanond Nong, Jérôme Tignon, Quentin Barbedienne, Nicolas Reyren, P. Bortolotti, Sukhdeep Dhillon, Sophie Collin, Henri Jaffrès, Laurent Vila, and Paul Noël
Subjects: Materials science, Transition metal, Spintronics, Ferromagnetism, Condensed matter physics, Hall effect, Spin Hall effect, Spin diffusion, Conductance, Spin (physics)
Abstract: It was recently reported that THz emission can be realized in ferromagnetic (FM) /non-FM bilayers via dynamical spin-to charge conversion originating from interfacial spin-orbit coupling or inverted spin-Hall effect (ISHE) [1-3]. We will present our results of THz emission provided by optimized grownth bilayers composed of a high-spin orbit material (Pt, Au :W) in contact with a thin ferromagnetic layer Co/Pt, NiFe/Au:W, NiFe/Au:Ta. Those bilayers are used in experiments combining RF-spin pumping and spin-to-charge conversion by ISHE [4-5]. In comparaison with Co/Pt systems, in NiFe/Au:Ta and NiFe/Au:W bilayers provide a smaller signal even though the spin Hall angles for Au:Ta and Au:W are larger than for Pt [6]. This is mainly due to their smaller spin-mixing conductance in comparaison with Co/Pt. We will discuss the role of the generalized spin-mixing conductance on the spin-transport properties and spin-orbit torques involved in the time-dependent diffusion and relaxation phenomena. We demonstrate that the THz signals strongly depend on the spin Hall angle of non-FM metal, spin diffusion length, and spin-mixing conductance. In the structures with large spin-mixing conductance and spin length diffusion, e.g., Co/Pt, the THz signal is comparable to ZnTe signal. It should be a rapid method to know the characteristic of spintronics samples. We have also studied in the static regime the unconventional Anomalous Hall effect (AHE) of Pt/[CoNi]_N multilayers showing up a characteristic AHE spin-inversion from Pt to Au:W samples by proximity effect. We analyze our results in the series of samples: the exact conductivity profile across the multilayers via the 'extended' Camley-Barnas approach [7] and the spin current profile generated by SHE. The values of spin Hall angles in layers are found: -0.2 for Pt (enhanced compared to CPP geometry)In [Co,Ni]N/Pt sample, we show that the transverse current changes from negative (N 20) values. [1] T. J. Huisman et al., Nat.Nano 11, 455–458 (2016) [2] T. Seifert et al., Nat.Photo 10, 483-488 (2016) [3] D. Yang et al., Adv.Opt.Mat. 4, 1944-1949 (2016) [4] J.C Rojas-Sanchez et al., PRL. 112, 106602 (2014) [5] P. Laczowski et al, APL 104, 142403 (2014) [6]P. Laczowski et al, Phys. Rev. B 96, 140405(R) (2017) [7] R. E. Camley et al., Phys. Rev. Lett. 63, 664 (1989); J. Barnas et al., Phys. Rev. B 42, 8110 (1990)
Published: 2018
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20. Electrical spin injection and detection in molybdenum disulfide multilayer channel (Conference Presentation)

Author: Yuan Lu, S. McMurtry, Shiheng Liang, Bingshan Tao, Huaiwen Yang, Henri Jaffrès, Sébastien Petit Watelot, Pierre Renucci, Stéphane Mangin, Jean-Marie George, and Xavier Marie
Subjects: Materials science, Spintronics, Transition metal, Condensed matter physics, Ferromagnetism, Spin polarization, Magnetoresistance, Monolayer, Spin diffusion, Quantum tunnelling
Abstract: Molybdenum disulfide has recently emerged as a promising two-dimensional semiconducting material for nano-electronic, opto-electronic and spintronic applications. However, the demonstration of an electron spin transport through a semiconducting MoS2 channel remains challenging. Here we show the evidence of the electrical spin injection and detection in the conduction band of a multilayer MoS2 semiconducting channel using a two-terminal spin-valve configuration geometry. A magnetoresistance around 1% has been observed through a 450 nm long, 6 monolayer thick MoS2 channel with a Co/MgO tunnelling spin injector and detector [1]. It is found that keeping a good balance between the interface resistance and channel resistance is mandatory for the observation of the two-terminal magnetoresistance. Moreover, the electron spin-relaxation is found to be greatly suppressed in the multilayer MoS2 channel with an in-plane spin polarization. The long spin diffusion length (approximately 235 nm) could open a new avenue for spintronic applications using multilayer transition metal dichalcogenides. In this talk, we will present the main issues of the spin-injection problem at ferromagnet/Tunnel barrier/MoS2 interfaces as well as the spin-propagation in multilayered channel like played by MoS2 involving Schottky depletion layers giving thus an extension to earlier modeling of spin-injection in ferromagnet/ssource/ferromagnet systems [2-3]. [1] Shiheng Liang et al., Nat. Comm. 8, 14947 (2017) [2] A. Fert, H. Jaffres, Phys Rev B64, 184420, 2001 [3] A. Fert, J.-M. George, H. Jaffres, R. Mattana, IEEE, 54, 921-932 (2007)
Published: 2018
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21. HVDC Overhead Line Insulators Selection and Design Update Features

Author: Luis F. Ferreira and Jean-Marie George
Subjects: Dc voltage, Mitigation methods, business.industry, Computer science, Electrical engineering, Stress conditions, Iec standards, Operating voltage, business, Overhead line
Abstract: The increasing number of HVDC projects has raised new interest in the design of components used in various materials dedicated to DC applications. For example, the unidirectional electric field in a dielectric subjected to a DC voltage generates specific stress conditions resulting in unique features making up the design of insulators. Likewise, the impact of polarization in the environment near a DC line requires special attention for airborne contamination which modifies the ability of a string of insulators to withstand the operating voltage under any circumstances. This paper will review the main features of DC overhead line insulators with specific details related to the various technologies available. Contamination aspects will also be discussed including the latest developments in IEC 60815 [1] as well as new mitigation methods for severe contamination conditions.
Published: 2018
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22. Bases and experimental validation of a novel VSPIN model: towards functional spin-controlled VCSELs

Author: Frougier Julien, Daniel Dolfi, Jean-Marie George, Ghaya Baili, Mehdi Alouini, Alexandre Joly, Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Thales Research and Technology [Palaiseau], THALES [France], École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Centre National de la Recherche Scientifique (CNRS)-THALES, and THALES
Subjects: Electromagnetic field, Physics, [PHYS]Physics [physics], Quantum decoherence, Spin-laser, Physics::Optics, Laser, Polarization (waves), 01 natural sciences, Computational physics, law.invention, Vertical-cavity surface-emitting laser, 010309 optics, law, Optical cavity, Polarization, 0103 physical sciences, 010306 general physics, Anisotropy, Eigenvalues and eigenvectors
Abstract: International audience; Optimization of spin-lasers relies on the proper design of the active medium but also on a thorough understanding of the vectorial dynamics of the electromagnetic field in the laser cavity itself. A vectorial approach based the Jones formalism associated to the resonant condition of the field in the laser cavity is derived in order to draw the main guidelines for developing functional spin-controlled VCSELs. This general modelling framework, which accounts for spin injection effects as a gain circular dichroism in the active medium, shows that any residual phase anisotropy in the laser has a detrimental role on polarization switching. The same framework, is used to propose two solutions enabling to overcome this drawback: either by compensating the phase anisotropy or by preparing the laser cavity so that its eigenstates are circularly polarized. Moreover, unlike in spin-LED, we show that the leverage effect existing in the laser due to eigenmodes coupling makes it possible to switch the laser from a polarized oscillation to the orthogonal one despite the weak spin injection efficiency due to spin decoherence. All these predictions are confirmed using external cavity VCSELs which offer an ideal playing field for experimental investigations. Based on these developments, future trends towards the achievement of efficient and compact spin-lasers will be given.
Published: 2018
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23. Excess velocity of magnetic domain walls close to the depinning field

Author: Sophie Collin, Lucas J. Albornoz, Jean Marie George, Juan-Carlos Rojas-Sánchez, Rebeca Diaz Pardo, Nirvana Caballero, A. B. Kolton, Sebastian Bustingorry, Vincent Jeudy, Javier Curiale, Iván Fernández Aguirre, Centro Atómico Bariloche [Argentine], Consejo Nacional de Investigaciones Científicas y Técnicas [Buenos Aires] (CONICET)-Comisión Nacional de Energía Atómica [ARGENTINA] (CNEA), Instituto Balseiro [Bariloche], Universidad Nacional de Cuyo [Mendoza] (UNCUYO)-Comisión Nacional de Energía Atómica [ARGENTINA] (CNEA), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Solides (LPS), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Comisión Nacional de Energía Atómica [ARGENTINA] (CNEA)-Universidad Nacional de Cuyo [Mendoza] (UNCUYO), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-THALES
Subjects: Kerr effect, Field (physics), Magnetic domain, Ciencias Físicas, FOS: Physical sciences, INGENIERÍAS Y TECNOLOGÍAS, 02 engineering and technology, 7. Clean energy, 01 natural sciences, purl.org/becyt/ford/1 [https], Condensed Matter::Superconductivity, purl.org/becyt/ford/2.10 [https], 0103 physical sciences, Phenomenological model, MULTILAYERS, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], NANOMAGNETISM, 010306 general physics, Nanotecnología, Physics, Condensed matter physics, Relaxation (NMR), Disordered Systems and Neural Networks (cond-mat.dis-nn), purl.org/becyt/ford/1.3 [https], Characteristic velocity, Condensed Matter - Disordered Systems and Neural Networks, Nano-materiales, 021001 nanoscience & nanotechnology, Magnetic field, Astronomía, DOMAIN WALL, Domain wall (magnetism), purl.org/becyt/ford/2 [https], 0210 nano-technology, CIENCIAS NATURALES Y EXACTAS
Abstract: Magnetic field driven domain wall velocities in [Co/Ni] based multilayers thin films have been measured using polar magneto-optic Kerr effect microscopy. The low field results are shown to be consistent with the universal creep regime of domain wall motion, characterized by a stretched exponential growth of the velocity with the inverse of the applied field. Approaching the depinning field from below results in an unexpected excess velocity with respect to the creep law. We analyze these results using scaling theory to show that this speeding up of domain wall motion can be interpreted as due to the increase of the size of the deterministic relaxation close to the depinning transition. We propose a phenomenological model to accurately fit the observed excess velocity and to obtain characteristic values for the depinning field Hd, the depinning temperature Td, and the characteristic velocity scale v0 for each sample. Fil: Caballero, Nirvana Belén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina Fil: Fernández Aguirre, Iván. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Cuyo; Argentina Fil: Albornoz, Lucas Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Cuyo; Argentina Fil: Kolton, Alejandro Benedykt. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Cuyo; Argentina Fil: Rojas Sanchez, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Université Paris Sud; Francia. Université de Lorraine. Institut Jean Lamour; Francia Fil: Collin, Sophie. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; Francia Fil: George, Jean Marie. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; Francia Fil: Diaz Pardo, Rebeca. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; Francia Fil: Jeudy, Vincent. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; Francia Fil: Bustingorry, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área Investigaciones y Aplicaciones No Nucleares. Gerencia de Física (CAB). Grupo de Teoría de Sólidos; Argentina Fil: Curiale, Carlos Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comision Nacional de Energía Atómica. Gerencia de Área Investigaciones y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Resonancias Magnéticas; Argentina
Published: 2017
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24. Very efficient electrical spin injection (/detection) into quantum dots at zero magnetic field

Author: Michel Hehn, Yuan Lu, X. F. Han, Pierre Renucci, Z.G. Wang, Bingshan Tao, Thierry Amand, Frougier Julien, Xavier Marie, Henri Jaffrès, Jean-Marie George, Bo Xu, Shiheng Liang, Hélène Carrère, Bernhard Urbaszek, Delphine Lagarde, Fabian Cadiz, Stéphane Mangin, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-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), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Institute of semiconductors [Chinese Academy of Sciences - Beijing] (IOS), Chinese Academy of Sciences [Beijing] (CAS), Institute of Semiconductors, Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-THALES, Chinese Academy of Science (CAS), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), and THALES-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Photon, Magnetism, Physics::Optics, Electrons, 02 engineering and technology, Zero field splitting, 01 natural sciences, Condensed Matter::Materials Science, Polarization, 0103 physical sciences, [CHIM]Chemical Sciences, 010306 general physics, Circular polarization, Photocurrent, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Condensed matter physics, Spin polarization, Quantum dots, Condensed Matter::Other, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Light emitting diodes, Magnetic field, Electroluminescence, Quantum dot, Anisotropy, 0210 nano-technology
Abstract: International audience; In this paper, we demonstrate a very efficient electrical spin injection into an ensemble of InAs/InGaAs quantum dots at zero magnetic field. The circular polarization of the electroluminescence coming from the dots, which are embedded into a GaAs-based Spin Light Emitting diode reaches a value as large as 20% at low temperature. In this device, no external magnetic field is required in order to inject or read spin polarization thanks to the use of an ultrathin CoFeB electrode (1.1 nm), as well as p-doped quantum dots (with one hole per dot in average) as an optical probe. The electroluminescence circular polarization of the dots follows the hysteresis loop of the magnetic layer and decreases as a function of bias for large voltages. In a reverse way, we have also investigated the possibility to use such a device as a photodetector presenting a photon helicity-dependent photocurrent. We observe a weak asymmetry of photocurrent under right and left polarized light that follows the hysteresis cycle of the magnetic layer, and the effect decreases for increasing temperatures and can be controlled by the bias
Published: 2017
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25. Non-local electrical spin injection and detection in germanium at room temperature

Author: Céline Vergnaud, Alain Marty, Michele Celebrano, Carlo Zucchetti, Jean-Philippe Attané, Julie Widiez, Henri Jaffrès, Matthieu Jamet, Alberto Ferrari, F. Rortais, Federico Bottegoni, Giovanni Isella, Franco Ciccacci, Jean-Marie George, Marco Finazzi, Lavinia Ghirardini, 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), 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)), Politecnico di Milano [Milan] (POLIMI), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), ANR-13-BS10-0002,SiGeSPIN,Spintronique dans le silicium et le germanium(2013), and THALES [France]-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Physics and Astronomy (miscellaneous), Silicon, chemistry.chemical_element, FOS: Physical sciences, Germanium, 02 engineering and technology, 01 natural sciences, Electric charge, Signal, Condensed Matter::Materials Science, 0103 physical sciences, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, Spin (physics), Condensed Matter - Materials Science, business.industry, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, 3. Good health, Tunnel magnetoresistance, Semiconductor, chemistry, Optoelectronics, Charge carrier, 0210 nano-technology, business
Abstract: Non-local carrier injection/detection schemes lie at the very foundation of information manipulation in integrated systems. This paradigm consists in controlling with an external signal the channel where charge carriers flow between a "source" and a well separated "drain". The next generation electronics may operate on the spin of carriers instead of their charge and germanium appears as the best hosting material to develop such a platform for its compatibility with mainstream silicon technology and the long electron spin lifetime at room temperature. Moreover, the energy proximity between the direct and indirect bandgaps allows for optical spin injection and detection within the telecommunication window. In this letter, we demonstrate injection of pure spin currents (\textit{i.e.} with no associated transport of electric charges) in germanium, combined with non-local spin detection blocks at room temperature. Spin injection is performed either electrically through a magnetic tunnel junction (MTJ) or optically, exploiting the ability of lithographed nanostructures to manipulate the distribution of circularly-polarized light in the semiconductor. Pure spin current detection is achieved using either a MTJ or the inverse spin-Hall effect (ISHE) across a platinum stripe. These results broaden the palette of tools available for the realization of opto-spintronic devices., Comment: 14 pages and 5 figures
Published: 2017
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26. Atomic scale structure and local chemistry of CoFeB-MgO perpendicular spin injector

Author: Bingshan Tao, Xavier Devaux, Philippe Barate, Pierre Renucci, Bo Xu, Julien Frougier, Michel Hehn, Stéphane Mangin, Henri Jaffres, Jean-Marie George, Xavier Marie, Xiufeng Han, Zhanguo Wang, and Yuan Lu
Published: 2016
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27. Topological spin-orbitronics (Conference Presentation)

Author: Karim Bouzehouane, Noah Van Horne, Amina Taleb-Ibrahimi, C. Vergnaud, Markus Weigand, Karin Garcia, Yu Fu, Laurent Vila, Vincent Cros, Constance Moreau-Luchaire, Jörg Raabe, Simón Oyarzún, Patrick Le Fèvre, Juan-Carlos Rojas-Sánchez, Davide Maccariello, Carlos A. F. Vaz, Joao Sampaio, Matthieu Jamet, François Bertran, Jean-Marie George, Yoshiyuki Ohtsubo, Phillip Wohlhüter, Nicolas Reyren, Peter Warnicke, Cyrile Deranlot, Serge Gambarelli, Albert Fert, Alain Marty, and Christoforos Moutafis
Subjects: Physics, Spin pumping, Spintronics, Condensed matter physics, Spin polarization, Magnetism, Topological insulator, Skyrmion, Condensed Matter::Strongly Correlated Electrons, Spin–orbit interaction, Topology, Spin-½
Abstract: Spintronics evolves along new paths involving non-magnetic materials having large spin-obit coupling, typically 5d metals, allowing for example large spin-to-charge current conversion (spin Hall and Rashba-Edelstein effects). These heavy metals have other effects: in proximity of magnetic thin films they can burst out the Dzyaloshinskii-Moriya interaction leading to the stabilization of chiral magnetic structures. Another source of recent interest relies on “non-trivial topologies”, either of the band structure of the topological insulators, or of the spin textures in magnetic thin films. We will discuss our recent progress to control the topological textures known as skyrmions in multilayers made of heavy metals and magnetic layers. Aiming at using skyrmions as magnetic bits in “racetrack memory” structures, one of the present challenges is to efficiently move skyrmions with dimensions of a few tens of nanometers. The topology of these magnetic structures imposes peculiar dynamics, interesting both in fundamental and applied perspectives. Simulations indicate that spin-orbit torques, through the absorption of the spin current generated by a nearby layer, should be the most efficient method. The conducting surfaces of topological insulators at which the carriers’ spin and momentum are locked, can display better spin-to-charge conversion than what is found using heavy metals. However, the control of the interfaces is crucial to conserve the Dirac cone and the associated spin-momentum locking. We demonstrate by ARPES and spin pumping experiments how the properties of the α-Sn thin film topological insulator are preserved and can be used for spintronics, maybe to move skyrmions!
Published: 2016
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28. Spin pumping and spin-orbit effects in Ge (Conference Presentation)

Author: Jean Philippe Attané, Stefan Blügel, C. Vergnaud, Stéphanie Pouget, Ashis Kumar Nandy, Matthieu Jamet, Serge Gambarelli, Henri Jaffrès, Laurent Vila, Jean Marie George, F. Rortais, Alain Marty, C. Beigné, Juan-Carlos Rojas-Sánchez, Simón Oyarzún, Hanako Okuno, and P. Laczkowski
Subjects: 010302 applied physics, Physics, Spin pumping, Condensed matter physics, Spintronics, Spin polarization, 02 engineering and technology, Magnetic semiconductor, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 01 natural sciences, Quantum spin Hall effect, Spin wave, 0103 physical sciences, Spin Hall effect, Spinplasmonics, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology
Abstract: The field of spintronics is based on the manipulation of the spin degree of freedom. It uses the carrier spin angular momentum as a basic functional unit in addition to the charge. The first requirement of a semiconductor-based spintronic technology is the efficient generation of spin-polarized carriers into the device heterostructure made of Si or Ge (the materials of mainstream microelectronics) at room temperature. In this presentation, we focus on the generation of a sizeable spin population into Ge by spin pumping. Spin pumping corresponds to the generation of a pure spin current in the Ge film by exciting the ferromagnetic resonance of an adjacent ferromagnetic electrode with microwaves. The pure spin current is then detected using spin-orbit based effects. Our aim is to understand the basic mechanisms of spin pumping into Ge as well as the spin-to-charge conversion by inverse spin Hall effect (ISHE, bulk effect) [1-4] and Rashba-Edelstein effect (interface effect) [5]. The influence of interface states is clearly demonstrated. Moreover, using the spin-split Rashba sub-surface states of the Ge(111) surface, we succeeded in demonstrating a giant conversion of a spin current generated by spin pumping into a charge current by the Rashba-Edelstein effect [6,7]. Our experimental findings are supported by ab-initio calculations. 1. Rojas-Sanchez, J.-C. et al. Spin pumping and inverse spin Hall effect in germanium. Phys. Rev. B 88, (2013). 2. Kato, Y. K., Myers, R. C., Gossard, A. C. and Awschalom, D. D. Observation of the spin Hall effect in semiconductors. Science 306, 1910–1913 (2004). 3. Valenzuela, S. O. and Tinkham, M. Direct electronic measurement of the spin Hall effect. Nature 442, 176–179 (2006). 4. Saitoh, E., Ueda, M., Miyajima, H. and Tatara, G. Conversion of spin current into charge current at room temperature: Inverse spin-Hall effect. Appl Phys Lett 88, 2509 (2006). 5. Bychkov, Y. A. and Rashba, E. I. Oscillatory effects and the magnetic susceptibility of carriers in inversion layers. Journal of Physics C: Solid State Physics 17, 6039–6045 (1984). 6. Edelstein, V. M. Spin polarization of conduction electrons induced by electric current in two-dimensional asymmetric electron systems. Solid State Communications 73, 233–235 (1990). 7. Rojas-Sanchez, J.-C. et al. Spin-to-charge conversion using Rashba coupling at the interface between non-magnetic materials. Nat Comms 4, (2013).
Published: 2016
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29. Spin Hall effect in 5d Au: W transition metal alloys (Conference Presentation)

Author: Patrick Warin, Yu Fu, Cyrile Deranlot, Albert Fert, Jean-Philippe Attane, Nicolas Reyren, Henri Jaffrès, Juan-Carlos Rojas-Sánchez, Alain Marty, Laurent Vila, W. Savero-Torres, P. Laczkowski, and Jean-Marie George
Subjects: Physics, Spin pumping, Condensed matter physics, Spin polarization, Spintronics, 02 engineering and technology, Spin–orbit interaction, 021001 nanoscience & nanotechnology, 01 natural sciences, Ferromagnetic resonance, Quantum spin Hall effect, 0103 physical sciences, Spin Hall effect, Spinplasmonics, Condensed Matter::Strongly Correlated Electrons, 010306 general physics, 0210 nano-technology, Computer Science::Cryptography and Security
Abstract: The spin Hall effect (SHE) [1] allows for a reciprocal conversion between charge and spin currents using the spin orbit coupling which can be at the core of several promising spintronics devices. The spin orbit interaction is used to produce a transverse flow of spin or charge in response to a longitudinal excitation, these are the direct or inverse SHE. The spin Hall angle (SHA), the ratio of longitudinal and transverse electronic conductivities, is the characterizing parameter of this conversion. So far, large SHA have been reported in transition metals like Pt, Pd, W, Beta-Ta and in a few alloys with large spin orbit coupling impurities: CuIr, CuBi or CuPb [2]. In this presentation we will report on our study of the SHA in AuW alloys [3] which exhibits a non-monotonic relation with the W concentration. In the regime of diluted alloys the behaviour suggests a dominant side-jump contribution to the spin Hall resistivity, the SHA increasing with the W concentration. We will present experiments demonstrating the requirement of new spin-absorption model in lateral spin valves adapted to the case of strong spin absorption for a correct evaluation of the SHA. Altogether with complementary Ferromagnetic Resonance Spin-Pumping studies, it then leads to SHA as large as +15%. At higher W content the SHA sign is reversed, becoming negative as for pure W.
Published: 2016
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30. Electrical spin injection and detection in molybdenum disulfide multilayer channel

Author: Shiheng Liang, Huaiwen Yang, Pierre Renucci, Bingshan Tao, Piotr Laczkowski, Stefan Mc-Murtry, Gang Wang, Xavier Marie, Jean-Marie George, Sébastien Petit-Watelot, Abdelhak Djeffal, Stéphane Mangin, Henri Jaffrès, Yuan Lu, Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), IMPACT N4S, ANR-15-IDEX-0004,LUE,Isite LUE(2015), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-THALES, Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), and THALES-Centre National de la Recherche Scientifique (CNRS)
Subjects: Science, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Article
Abstract: Molybdenum disulfide has recently emerged as a promising two-dimensional semiconducting material for nano-electronic, opto-electronic and spintronic applications. However, the demonstration of an electron spin transport through a semiconducting MoS2 channel remains challenging. Here we show the evidence of the electrical spin injection and detection in the conduction band of a multilayer MoS2 semiconducting channel using a two-terminal spin-valve configuration geometry. A magnetoresistance around 1% has been observed through a 450 nm long, 6 monolayer thick MoS2 channel with a Co/MgO tunnelling spin injector and detector. It is found that keeping a good balance between the interface resistance and channel resistance is mandatory for the observation of the two-terminal magnetoresistance. Moreover, the electron spin-relaxation is found to be greatly suppressed in the multilayer MoS2 channel with an in-plane spin polarization. The long spin diffusion length (approximately ∼235 nm) could open a new avenue for spintronic applications using multilayer transition metal dichalcogenides., MoS2 is a promising two-dimensional candidate for opto-electronic and spintronic applications. Here, the authors report electrical spin injection and detection in a few-layered MoS2 channel, demonstrating that the spin diffusion length is at least 235 nm in MoS2 conduction band.
Published: 2016
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31. Spin Transport in Organic Semiconductors

Author: Jean-Marie George and Henri Jaffrès
Subjects: Materials science, Condensed matter physics, Magnetoresistance, Spin transfer, Quantum tunnelling
Published: 2016
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32. A proposed technique to improve the filling of the mold cavity by polymer during injection molding

Author: Eric Arquis, Nicolas Regnier, Jean-Marie George, Guy Defaye, and Hamdy Hassan
Subjects: chemistry.chemical_classification, Materials science, Polymers and Plastics, Mechanical engineering, General Chemistry, Polymer, Molding (process), medicine.disease_cause, Coolant, Volumetric flow rate, chemistry, Mold, Materials Chemistry, medicine, Experimental work, Composite material, Cooling fluid
Abstract: In this study, a technique is proposed to improve the filling process of the injection molding and minimize the solidification during the filling to achieve a complete filling of the mold cavity. Two methods are proposed: stopping the flow rate of the cooling fluid or passing cooling fluid inside the cooling channels at higher temperature during a period of the injection molding cycle. The configuration studied consists of the mold with cuboids-shape cavity having two different thicknesses. A validation of the numerical model used by an experimental work is presented. The results show that, stopping of cooling fluid on a period of injection cycle has not great effect on the improvement of injection cycle. The results indicate that passing coolant fluid at higher temperature during the ejection stage decreases the solidification of the polymer during the filling stage by about 40%. © POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers.
Published: 2011
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33. Theoretical and experimental investigation of optically spin-injected VECSEL

Author: Alexandre Joly, Isabelle Sagnes, Ghaya Baili, Daniel Dolfi, Jean-Marie George, Frougier Julien, Mehdi Alouini, TRT Thales Reasearch & Technology, THALES, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Association of Computer Electronics and Electrical Engineers (ACEEE), Institute of Doctors Engineers and Scientists, Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Thales Research and Technology [Palaiseau], THALES-Centre National de la Recherche Scientifique (CNRS), THALES [France], THALES [France]-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Quantum well lasers, Amplified spontaneous emission, Materials science, Physics::Optics, 02 engineering and technology, Spin dynamics, VECSEL, Elliptical polarization, Surface emitting lasers, 01 natural sciences, Optical pumping, Laser dynamics, Optics, Tunnel junctions, Polarization, 0103 physical sciences, Birefringence measurements, Laser polarization, 010306 general physics, Semiconductor quantum wells, Circular polarization, [PHYS]Physics [physics], Birefringence, Polarization rotator, business.industry, Linear polarization, Spin injection, Nanoelectronics, Laser optics, Circular polarization state, Semiconducting indium compounds, 021001 nanoscience & nanotechnology, Polarization (waves), Amplified spontaneous emissions, Anisotropy, Optoelectronics, 0210 nano-technology, business, Experimental investigations
Abstract: International audience; We report theoretical and experimental analysis of spin-injected VECSELs. First, we fabricate and characterize an optically pumped (100)-oriented InGaAs/GaAsP multiple quantum well VECSEL. The structure is designed to allow the integration of a Metal-Tunnel-Junction ferromagnetic spin-injector for future electrical injection. We report here the control at room temperature of the VECSEL polarization using optical spin injection in the active medium. The switching between two highly circular polarization states had been demonstrated using an M-shaped extended cavity in multi-modes lasing. This first result witnesses an efficient spin-injection in the active medium of the laser. Then, we report birefringence measurements of the VECSEL in oscillating conditions. The proposed technique relies on the measurement in the microwave domain of the beatnote between the oscillating mode and the amplified spontaneous emission of the cross-polarized non-lasing field lying in the following longitudinal mode. This technique is shown to offer extremely high sensitivity and accuracy enabling to track the amount of residual birefringence according to the laser operation conditions. Finally, we discuss the compensation of the residual linear phase anisotropy by controlling the birefringence of an intracavity electro-optical crystal. A 44-fold birefringence reduction is obtained. Besides, we study the modification of the laser polarization eigen states with birefringence compensation: a rotation of the linear polarization state is observed when the total phase anisotropy is reduced. An elliptical polarization eigen state is obtained at the minimum of the birefringence into the laser cavity, more favorable for spin injection. © 2016 SPIE.
Published: 2016
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34. Verres pour l'isolement électrique

Author: Jean-Marie George
Abstract: Parmi les materiaux ayant des caracteristiques electriques isolantes, le verre s’affirme comme un candidat ideal. Son utilisation est cependant conditionnee par la maniere dont les contraintes mecaniques sont apprehendees. De ce fait, les applications du verre dans le domaine de l’isolement electrique se retrouvent soit dans le domaine des verres trempes soit dans des technologies ou le verre est utilise a l’etat de fibres de renforcement de polymeres. Chacun de ces deux domaines sera aborde dans cet article en partant de la chimie des materiaux et des modes de fabrication de ces isolants, avec une description des contraintes electrique, mecanique et chimique auxquelles ils sont soumis et des particularites des domaines d’applications dans lesquels on retrouve l’une ou l’autre de ces technologies.
Published: 2016
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35. Electrical control of the perpendicular magnetization in Pt/[Co/Ni]3/Al multilayers (Presentation Recording)

Author: Albert Fert, Cyrile Deranlot, Jean-Marie George, Alexandra Mougin, Sophie Collin, Juan-Carlos Rojas-Sánchez, Henri Jaffrès, Nicolas Reyren, P. Laczkowski, and Joao Sampaio
Subjects: Physics, Magnetization, Domain wall (magnetism), Condensed matter physics, Spintronics, Hall effect, Topological insulator, Spin Hall effect, Dielectric, Spin (physics)
Abstract: The spin to charge current conversion (SCCC) due to spin-orbit coupling (SOC) opens the way to manipulate the magnetization by electrical means. SCCC results either from bulk effects, in particular through Spin Hall Effect (SHE) [1-3], or from interfacial effects, for example in our recent experimental discovery of Rashba-Edelstein Effect (REE) [4]. We have investigated the SCCC by SHE in metals such as Pt [1,2], Au and AuW [3]. In the case of 2D systems, we recently demonstrated a large SCCC efficiency in Rashba type Ag/Bi interface [4]. An even larger effect can be even anticipated if topological insulators are used. We will present a practical application of this SCCC to control the magnetization due to the spin-orbit torque induced by SHE [5-8], and focus on the case of Pt/(Co/Ni)3/Al multilayers with perpendicular magnetization. Using both the anomalous Hall Effect and Kerr experiments in patterned Hall bars, we are able to establish a scenario for the reversal mechanism involving domain wall motions and spin-orbit torques induced by SHE in Pt. [1] J-C. Rojas-Sanchez et al. PRL 112, 106602 (2014). [2] J.-C. Rojas-Sanchez et al. SPIE 9167, Spintronics VII, 916729 (2014). [3] P. Laczkowski et al. APL 104, 142403 (2014). [4] J C Rojas Sanchez et al. Nat. Comm. 4:2944 (2013). [5] A. V. Khvalkovskiy et al. PRB 87, 020402 (2013). [6] I. M. Miron et al. Nature 476, 189 (2011). [7] L. Liu et al. PRL 109, 096602 (2012). [8] N. Perez et al. APL 104, 092403 (2014).
Published: 2015
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36. Accurate measurement of the residual birefringence in VECSEL: Towards understanding of the polarization behavior under spin-polarized pumping

Author: Frougier Julien, Isabelle Sagnes, Ghaya Baili, Daniel Dolfi, Jean-Marie George, Mehdi Alouini, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Thales Research and Technology [Palaiseau], THALES [France], Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Association of Computer Electronics and Electrical Engineers (ACEEE), Institute of Doctors Engineers and Scientists, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), ANR-10-BLAN-1014, French National Research Agency (ANR), ANR-10-BLAN-1014,INSPIRE,Injection de Spin pour l'émission de lumière polarisée(2010), THALES-Centre National de la Recherche Scientifique (CNRS), THALES, Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Amplified spontaneous emission, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Materials science, Birefringence, business.industry, Physics::Optics, 02 engineering and technology, 021001 nanoscience & nanotechnology, Polarization (waves), Laser, 01 natural sciences, Vertical-external-cavity surface-emitting-laser, Atomic and Molecular Physics, and Optics, Semiconductor laser theory, law.invention, Longitudinal mode, Optics, law, 0103 physical sciences, Optoelectronics, 010306 general physics, 0210 nano-technology, business, Microwave, ComputingMilieux_MISCELLANEOUS
Abstract: In this paper we report birefringence measurements of an optically pumped (100)-oriented InGaAs/GaAsP multiple quantum well (MQWs) Vertical External Cavity Surface Emitting Laser (VECSEL) in oscillating conditions. The proposed technique relies on the measurement in the microwave domain of the beatnote between the oscillating mode and the amplified spontaneous emission of the cross-polarized non-lasing field lying in the following longitudinal mode. This technique is shown to offer extremely high sensitivity and accuracy enabling to track the amount of residual birefringence according to the laser operation conditions. The experience fits within the broader framework of polarization selection in spin-injected lasers.
Published: 2015
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37. Electrical Spin-Injection enhancement in III-V Spin-LEDs: Towards control of light polarization using spin-injected Lasers

Author: Julien Frougier, Tiantian Zhang, Shiheng Liang, Phillipe Barate, Pierre Renucci, Xavier Marie, Ghaya Baili, Mehdi Alouini, Isabelle Sagnes, Arnaud Garnache, Jaffrès, H., Yuan LU, Jean-Marie George, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), National Astronomical Observatories [Beijing] (NAOC), Chinese Academy of Sciences [Beijing] (CAS), Département de Recherche en Ingéniérie des Véhicules pour l'Environnement (DRIVE), Université de Bourgogne (UB), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Thales Research and Technology [Palaiseau], THALES [France], Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Institut d’Electronique et des Systèmes (IES), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Térahertz, hyperfréquence et optique (TéHO), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Department of Electrical Engineering, University of Nebraska–Lincoln, University of Nebraska System-University of Nebraska System, Association of Computer Electronics and Electrical Engineers (ACEEE), Institute of Doctors Engineers and Scientists, Unité mixte de physique CNRS/Thalès ( UMP CNRS/THALES ), THALES-Centre National de la Recherche Scientifique ( CNRS ), National Astronomical Observatories [Beijing] ( NAOC ), Chinese Academy of Sciences [Beijing] ( CAS ), Département de Recherche en Ingéniérie des Véhicules pour l'Environnement ( DRIVE ), Université de Bourgogne ( UB ), Institut National des Sciences Appliquées - Toulouse ( INSA Toulouse ), Institut National des Sciences Appliquées ( INSA ), Laboratoire de physique et chimie des nano-objets ( LPCNO ), Institut National des Sciences Appliquées ( INSA ) -Institut National des Sciences Appliquées ( INSA ) -Université Paul Sabatier - Toulouse 3 ( UPS ) -Centre National de la Recherche Scientifique ( CNRS ), THALES, Institut de Physique de Rennes ( IPR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de photonique et de nanostructures ( LPN ), Centre National de la Recherche Scientifique ( CNRS ), Institut d’Electronique et des Systèmes ( IES ), Université de Montpellier ( UM ) -Centre National de la Recherche Scientifique ( CNRS ), University of Nebraska-Lincoln, THALES-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), University of Nebraska [Lincoln], and Carré, Anthony
Subjects: [PHYS.PHYS.PHYS-OPTICS] Physics [physics]/Physics [physics]/Optics [physics.optics], [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], [ PHYS.PHYS.PHYS-OPTICS ] Physics [physics]/Physics [physics]/Optics [physics.optics], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2013

38. Transition from spin accumulation into interface states to spin injection in silicon and germanium conduction bands

Author: A. Jain, Matthieu Jamet, Jean-Christophe Le Breton, Jean-Philippe Attané, Juan-Carlos Rojas-Sánchez, Laurent Vila, Céline Vergnaud, Jean-Marie George, J. Peiro, Emmanuel Augendre, M. Cubukcu, Serge Gambarelli, Henri Jaffrès, Service de Physique des Matériaux et Microstructures (SP2M - UMR 9002), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), 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), Service de Chimie Inorganique et Biologique (SCIB - UMR E3), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-THALES, Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Spin pumping, Materials science, Spintronics, Spin polarization, Condensed matter physics, 02 engineering and technology, Magnetic semiconductor, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Condensed Matter::Materials Science, Spin wave, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Spinplasmonics, Spin diffusion, Spin Hall effect, Condensed Matter::Strongly Correlated Electrons, 010306 general physics, 0210 nano-technology
Abstract: International audience; Electrical spin injection into semiconductors paves the way for exploring new phenomena in the area of spin physics and new generations of spintronic devices. However the exact role of interface states in the electrical spin injection mechanism from a magnetic tunnel junction into a semiconductor is still under debate. Here we demonstrate a clear transition from spin accumulation into interface states to spin injection in the conduction band of n-Si and n-Ge using a CoFeB/MgO tunnel contact. We observe spin signal amplification at low temperature due to spin accumulation into interface states followed by a clear transition towards spin injection in the conduction band from approximately 150 K up to room temperature. In this regime, the spin signal is reduced down to a value compatible with the standard spin diffusion model. More interestingly, in the case of germanium, we demonstrate a significant modulation of the spin signal by applying a back-gate voltage to the conduction channel. We also observe the inverse spin Hall effect in Ge by spin pumping from the CoFeB electrode. Both observations are consistent with spin accumulation in the Ge conduction band.
Published: 2013
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39. The new era of spintronics

Author: Richard Mattana, Pierre Seneor, Henri Jaffrès, Albert Fert, and Jean-Marie George
Subjects: Materials science, Spintronics, General Physics and Astronomy, Nanotechnology
Published: 2003
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40. Magnetic properties and domain structure of epitaxial (001) Fe/Pd superlattices

Author: P. Galtier, Jacques Miltat, R. Kergoat, Jean-Marie George, Olivier Durand, Jeffrey R. Childress, and Alain Schuhl
Subjects: Condensed Matter::Materials Science, Magnetization, Magnetic anisotropy, Materials science, Magnetic domain, Ferromagnetism, Condensed matter physics, Superlattice, Coercivity, Condensed Matter Physics, Anisotropy, Electronic, Optical and Magnetic Materials, Molecular beam epitaxy
Abstract: The magnetic properties of well-characterized (001)Fe/Pd superlattices prepared by molecular beam epitaxy are presented. The saturation magnetization is enhanced due to the polarization of the Pd interface, and analysis of hysteresis loops indicate low coercive fields, abrupt magnetic reversals, and ferromagnetic coupling between the Fe layers for all Pd thickness investigated (10–50 A). It is also found that deposition on a stationary substrate can create a weak uniaxial in-plane anisotropy, which, for one of the two easy directions of Fe, causes a spontaneous rotation of the magnetization by 90° at low fields. This effect is clearly demonstrated by optical Kerr-effect imaging of the magnetic domain structure, and can be mistaken for antiferromagnetic coupling with very weak coupling fields. The strength of this uniaxial anisotropy is found to oscillate rapidly with Pd thickness, suggesting that it is very sensitive to the microstructure.
Published: 1994
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41. Inverse spin-valve-type magnetoresistance in spin engineered multilayered structures

Author: Agnès Barthélémy, Jean-Luc Duvail, Frédéric Petroff, Jean-Marie George, Luis Gustavo Pereira, L. B. Steren, Peter A. Schroeder, Paul Holody, Reza Loloee, and Albert Fert
Subjects: Física da matéria condensada, Materia condensada, Magnetorresistência, Materials science, Magnetoresistance, Condensed matter physics, Spin valve, General Physics and Astronomy, Inverse, Type (model theory), Magnetização, Condutividade elétrica, Spin-½
Abstract: The resistivity of magnetic multilayers is generally smaller when the magnetizations of successive layers are parallel, which is the so-called giant magnetoresistance or spin-valve effect. We have been able to reverse this effect and to obtain a smaller resistivity for an antiparallel arrangement by intercalating thin Cr layers within half of the Fe layers in Fe/Cu multilayers. This inverse spin-valve elfect is due to the inverse spin asymmetries of the electron scattering in successive Fe layers with and without Cr. This is a confirmation of the fundamental mechanism of the giant magnetoresistance.
Published: 1994
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42. Depth analysis of boron diffusion in MgO/CoFeB bilayer by x-ray photoelectron spectroscopy

Author: Guy Jézéquel, Cyrile Deranlot, Aurélien Renard, Yuan Lu, Bruno Lépine, M. Alnot, Henri Jaffrès, Frédéric Petroff, J. Lambert, Martine Mullet, S. Ababou, Jean-Marie George, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010302 applied physics, [PHYS]Physics [physics], Nanostructure, Materials science, Annealing (metallurgy), Bilayer, General Physics and Astronomy, chemistry.chemical_element, Heterojunction, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, law.invention, Crystallography, X-ray photoelectron spectroscopy, chemistry, law, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Boron diffusion, Crystallization, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology, Boron
Abstract: International audience; We have studied the boron B diffusion in MgO/CoFeB bilayer by x-ray photoelectronspectroscopy depth analysis. A large concentration of B B/Mg=0.16 was found to diffuse into theMgO barrier after 350 °C annealing. The boron in MgO is in a highly oxidized B3+ state and ishomogenously distributed in the whole barrier. The important B diffusion in MgO could be relatedto the CoFeB crystallization process which begins from the under CoFeB/Ru interface and pushesboron atoms to diffuse into the MgO barrier during annealing.
Published: 2010
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43. Electrical Spin Injection in Hybrid Ferromagnetic Metal/Semiconductor Structures

Author: Xavier Marie, Pierre Renucci, Henri Jaffrès, Thierry Amand, and Jean-Marie George
Subjects: Spin pumping, Materials science, Ferromagnetism, Condensed matter physics, Spin injection, Metal semiconductor
Published: 2010
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44. Magnetic vortices in nanowires with transverse easy axis

Author: Armando Encinas, Andre Thiaville, Laurent Vila, Giancarlo Faini, Ursula Ebels, Jean-Marie George, Michaël Darques, Luc Piraux, and UCL - FSA/MAPR - Département des sciences des matériaux et des procédés
Subjects: Materials science, Field (physics), Condensed matter physics, demagnetisation, Nanowire, vortices, Condensed Matter Physics, Magnetocrystalline anisotropy, Chirality (electromagnetism), cobalt, galvanomagnetic effects, Electronic, Optical and Magnetic Materials, Vortex, Magnetic anisotropy, Magnetization, Transverse plane, Condensed Matter::Materials Science, nanowires, magnetisation reversal
Abstract: We present magnetotransport measurements as well as micromagnetic simulations of magnetization reversal in magnetic nanowires having strong transverse magnetocrystalline anisotropy. The interplay between exchange, demagnetizing, and magnetocrystalline energies gives rise to a micromagnetic configuration involving vortices with alternative chirality along the wire. Despite the complexity of the field angle-dependent magnetization reversal process, a very good agreement is obtained between experiments and simulations. This provides evidence that the reported magnetization process appears generally in nanowires with strong transverse magnetocrystalline anisotropy. Moreover an analytical expression is established for the angular dependency of the core switching field. The simulations indicate the occurrence of Bloch points during the core reversal.
Published: 2009

45. Strain-Control of the magnetic anisotropy in (Ga,Mn)(As,P) ferromagnetic semiconductor layers

Author: Michael Tran, Catherine Gourdon, Vincent Jeudy, Olivia Mauguin, Ludovic Largeau, Laurent Travers, Aristide Lemaître, Audrey Miard, Jean-Marie George, Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, ANR-05-NANO-0072,MOMES,Manipulation Optique, Magnétisme, Electronique de Spin(2005), and THALES [France]-Centre National de la Recherche Scientifique (CNRS)
Subjects: Condensed Matter - Materials Science, magnetic anisotropy, Materials science, Physics and Astronomy (miscellaneous), Strain (chemistry), Condensed matter physics, Magnetization reversal, ferromagnetic semiconductor, 75.50.Pp, 75.30.Gw, 75.70.Ak, 75.60.Ch, Ferromagnetic semiconductor, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, 02 engineering and technology, Substrate (electronics), 021001 nanoscience & nanotechnology, Epitaxy, 01 natural sciences, Magnetic anisotropy, Domain wall (magnetism), Ferromagnetism, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 010306 general physics, 0210 nano-technology
Abstract: International audience; A small fraction of phosphorus (up to 10 %) was incorporated in ferromagnetic (Ga,Mn)As epilayers grown on a GaAs substrate. P incorporation allows reducing the epitaxial strain or even change its sign, resulting in strong modifications of the magnetic anisotropy. In particular a reorientation of the easy axis toward the growth direction is observed for high P concentration. It offers an interesting alternative to the metamorphic approach, in particular for magnetization reversal experiments where epitaxial defects stongly affect the domain wall propagation.
Published: 2008
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46. Spintronic with semiconductors

Author: Marc Elsen, Jean-Marie George, Richard Mattana, Vincent Garcia, Henri Jaffrès, Institut des Nanosciences de Paris (INSP), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Magnetoresistance, Energy Engineering and Power Technology, Giant magnetoresistance, 02 engineering and technology, semiconductors, 01 natural sciences, law.invention, law, 0103 physical sciences, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, spintronic, Spin pumping, Condensed matter physics, Spintronics, business.industry, Transistor, General Engineering, Magnetic semiconductor, 021001 nanoscience & nanotechnology, Engineering physics, ferromagnetism, Tunnel magnetoresistance, Semiconductor, 0210 nano-technology, business
Abstract: International audience; Soon afterwards the discovery of the giant magnetoresistance in metallic multilayers, researchers have attempted to integrate spintronic properties with semiconductor materials. They came up against several difficulties related to the structural and electronic properties of the ferromagnetic metal-semiconductor interface. We will report on the recent progress made in this field of spintronic with semiconductors. First of all we will explain the interfacial resistance conditions required to inject and detect efficient spin current in a semiconductor and in a second part we will show that efficient spin injection experiments have been now achieved thanks to the addition of a tunnel resistance at the interface. We will then report on the magnetoresistance experiment performed with diluted magnetic semiconductors as ferromagnetic material. This type of material can constitute an alternative road to achieving electrical control spintronic devices. Finally, we will finish by reporting on research for a highly spin-polarized source to inject spin-polarized current in a semiconductor. It will be mainly focused on tunnel magnetoresistance junctions with semiconductor barriers and hot electron transistor. To cite this article: J.-M. George et al., C R. Physique 6 (2005). (c) 2005 Academie des sciences. Published by Elsevier SAS. All rights reserved.
Published: 2005
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47. Magnetization reversal by injection and transfer of spin: experiments and theory

Author: Henri Jaffrès, Giancarlo Faini, Vincent Cros, Julie Grollier, Annie Vaures, Jean-Marie George, J. Ben Youssef, Albert Fert, Amir Hamzić, H. Le Gall, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, Université Paris-Sud - Paris 11 (UP11), University of Zagreb, Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Laboratoire de magnétisme de Bretagne (LMB), Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), and Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Condensed Matter - Materials Science, Materials science, Spintronics, Condensed matter physics, Magnetization reversal, Spin transport, Spin transfer, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Magnetic field, Magnetization, Ferromagnetism, 0103 physical sciences, Torque, Current (fluid), [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, Spin-½
Abstract: Reversing the magnetization of a ferromagnet by spin transfer from a current, rather than by applying a magnetic field, is the central idea of an extensive current research. After a review of our experiments of current-induced magnetization reversal in Co/Cu/Co trilayered pillars, we present the model we have worked out for the calculation of the current-induced torque and the interpretation of the experiments.
Published: 2004
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48. Field dependence of magnetization reversal by spin transfer

Author: H. Jaffrès, J. Ben Youssef, Jean-Marie George, H. Le Gall, Vincent Cros, Giancarlo Faini, Albert Fert, Amir Hamzić, and Julie Grollier
Subjects: Physics, Condensed Matter - Materials Science, Condensed matter physics, Magnetization reversal, magnetization reversal mechanisms, magnetic properties of interfaces (multilayers, superlattices, heterostructures), electronic transport in interface structures, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Field dependence, Spin transfer, Instability
Abstract: We describe and analyze the effect of an applied field ${(H}_{\mathrm{appl}})$ on the current-driven magnetization reversal in pillar-shaped Co/Cu/Co trilayers. Depending on the magnitude of ${H}_{\mathrm{appl}},$ we observe two different types of transitions between the parallel (P) and antiparallel (AP) magnetic configurations of the the Co layers. If ${H}_{\mathrm{appl}}$ is smaller than some threshold value, the transitions between P and AP are relatively sharp and irreversible. For ${H}_{\mathrm{appl}}$ exceeding this threshold value, the transitions are progressive and reversible. We show that this behavior can be precisely accounted for by introducing the current-induced torque of the spin transfer models into a Landau-Lifshitz-Gilbert equation to determine the stability or instability of the P and AP states. This analysis also provides a good description for the field dependence of the critical currents.
Published: 2003
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49. Epitaxial spin‐valve structures for ultra‐low‐field detection

Author: Olivier Durand, Alain Schuhl, Jean-Marie George, Jeffrey R. Childress, and Luis Gustavo Pereira
Subjects: Materials science, Condensed matter physics, Magnetoresistance, Scattering, Bilayer, Spin valve, General Physics and Astronomy, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Epitaxy, Magnetic field, Condensed Matter::Materials Science, Magnetization, Impurity, Condensed Matter::Superconductivity
Abstract: A new epitaxial ‘‘spin‐valve’’‐type system for low‐field magnetoresistive detection is described. This system is based on Fe/Pd epitaxial multilayers grown on (100)MgO by MBE. These films show a very abrupt transition from positive to negative magnetization as the reverse field is applied during hysteresis measurements. We have used these sensitive magnetic properties to fabricate epitaxial spin‐valve structures by epitaxial growth of Fe/Ag, Co/Ag, or Co/Cu bilayers on top of a Fe/Pd bilayer. Hysteresis loops and magnetoresistance curves clearly indicate a significant field range with antiparallel alignment of the two components. Magnetoresistive sensitivities of up to 0.3% per Oe at low temperatures have been observed in these structures. The efficiency of the spin‐dependent scattering has subsequently been improved either through the addition of planar Co impurities, in both the soft and hard magnetic layer, or by increasing the number of active Fe/Pd interfaces. This approach leads to a drastic improve...
Published: 1994
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50. Spin Signal in Metallic Lateral Spin Valves Made by a Multiple Angle Evaporation Technique

Author: Takashi Kimura, Tao Yang, Yoshichika Otani, Piotr Łączkowski, Laurent Vila, Albert Fert, Alain Marty, Jean-Philippe Attané, Henri Jaffrès, Jean-Marie George, and Sara E. Ferry
Subjects: Fabrication, Materials science, business.industry, General Engineering, Nanowire, General Physics and Astronomy, Nanotechnology, Evaporation (deposition), Signal, Metal, Resist, Ferromagnetism, visual_art, visual_art.visual_art_medium, Optoelectronics, business, Spin-½
Abstract: We report on the fabrication of metallic lateral spin valves using different evaporation directions for respective ferromagnetic and nonmagnetic materials. In this way, we can fabricate and connect different nanowires through the same resist mask in a single evaporation sequence, avoiding interface contamination. With this technique and by reducing the wire widths down to 50 nm, we obtained spin signals as large as 24 mΩ at 77 K in devices with transparent interfaces. We studied the influence of the nonmagnetic metal. Spin signals are found to be much larger for Al and Cu than for Au-based devices.
Published: 2011
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