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1. Tunability Investigation in the BaTiO3-CaTiO3-BaZrO3 Phase Diagram Using a Refined Combinatorial Thin Film Approach

Author

B. Negulescu, Patrick Poveda, Mario Maglione, Quentin Simon, Sandrine Payan, P. Gardes, Nazir Jaber, Christophe Daumont, Jérôme Wolfman, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), STMicroelectronics, This research was funded by Investissement d’Avenir project Tours2015 and by Région Centre Val de Loire ARD Project MAPS., Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Université de Tours-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, 02 engineering and technology, Dielectric, 01 natural sciences, Pulsed laser deposition, law.invention, law, 0103 physical sciences, lead-free relaxor, Materials Chemistry, Figure of merit, Breakdown voltage, Thin film, dielectric, 010302 applied physics, BCTZ, business.industry, Surfaces and Interfaces, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Engineering (General). Civil engineering (General), Ferroelectricity, Surfaces, Coatings and Films, Capacitor, thin films, tunable capacitors, Optoelectronics, Dielectric loss, TA1-2040, PLD, 0210 nano-technology, business
Abstract

Tunable ferroelectric capacitors, which exhibit a decrease in the dielectric permittivity under an electric field, are widely used in electronics for RF tunable applications. Current devices use barium strontium titanate (BST) as the tunable dielectric, but new applications call for tunable materials with specific performance improvements. It is then of crucial importance to dispose of a large panel of electrically characterized materials to identify the most suited compound for a given set of device specifications. Here, we report on the dielectric tuning properties of Ba1−xCaxTi1−yZryO3 (BCTZ) thin films libraries (0 ≤ x ≤ 30% and 0 ≤ y ≤ 28.5%) synthesized by combinatorial pulsed laser deposition (CPLD). An original CPLD approach allowing reliable and statistical ternary phase diagrams exploration is reported. The effects of Ca and Zr content on tunability, breakdown voltage and dielectric losses are explicated and shown to be beneficial up to a certain amount. Compounds close to (Ba0.84Ca0.16)(Ti0.8Zr0.2)O3 exhibit the highest figures of merit, while a zone with compositions around (Ba0.91Ca0.09)(Ti0.81Zr0.19)O3 show the best compromise between tuning ratio and figure of merit. These results highlight the potential of BCTZ thin films for electrically tunable applications.

Published
2021
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2. Structural and chemical investigation of interface related magnetoelectric effect in Ni/BiFe0.95Mn0.05O3 heterostructures

Author

Christophe Daumont, Pascal Andreazza, Sylvie Schamm-Chardon, Jérôme Wolfman, Thibaud Denneulin, Nazir Jaber, B. Negulescu, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Université de Tours-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Interfaces, Confinement, Matériaux et Nanostructures ( ICMN), Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Matériaux et dispositifs pour l'Electronique et le Magnétisme (CEMES-MEM), Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), 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 de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), 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)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université de Tours (UT)-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), 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), 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)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Photoemission spectroscopy, Magnetoelectric effect, General Physics and Astronomy, 02 engineering and technology, Multiferroic, 010402 general chemistry, 01 natural sciences, Magnetoelectric coupling, Multiferroics, Ferroelectric structure, Condensed matter physics, Electron energy loss spectroscopy, Heterojunction, Surfaces and Interfaces, General Chemistry, Ionic migration, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Ferroelectricity, Exchange coupling, 0104 chemical sciences, Surfaces, Coatings and Films, Reciprocal lattice, Transmission electron microscopy, BiFeO3 thin film, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology
Abstract

International audience; The magnetoelectric coupling mechanism in Ni/BiFe0.95Mn0.05O3 heterostructures is investigated through a detailed microstructural study of the BiFe0.95Mn0.05O3 film and a chemical analysis of the Ni/BiFe0.95Mn0.05O3 interface. The four structural variants expected in BiFe0.95Mn0.05O3 are detected by high resolution X-ray diffraction reciprocal space mapping method. The ferroelectric domain structure is imaged with transmission electron microscopy. Oxidized Ni is evidenced at the Ni/BiFe0.95Mn0.05O3 interface by electron energy loss spectroscopy and X-ray photoemission spectroscopy, although the degree of Ni oxidation is independent of the magnetoelectric state of the heterostructure.

Published
2019
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3. Extreme dielectric non-linearities at the convergence point in Ba1-xCaxTi1-xZrxO3 thin films

Author

Patrick Poveda, Mario Maglione, Quentin Simon, Jérôme Wolfman, Sandrine Payan, Christophe Daumont, P. Gardes, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), STMicroelectronics [Tours] (ST-TOURS), the French government and STMicroelectronics through the project Investissement d’Avenir Tours2015, and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Permittivity, Materials science, Dielectric, 02 engineering and technology, 01 natural sciences, law.invention, Tetragonal crystal system, law, Electric field, Phase (matter), 0103 physical sciences, Materials Chemistry, Thin film, Tunable capacitors, 010302 applied physics, BCTZ, Condensed matter physics, Mechanical Engineering, Metals and Alloys, Sputtering, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Ferroelectricity, Capacitor, Lead-free relaxor, Mechanics of Materials, 0210 nano-technology
Abstract

International audience; The dielectric properties of Ba1-xCaxTi1-xZrxO3 (BCTZ) thin films are explored by varying x from 0 to 0.18 through an RF magnetron co-sputtering process. Thin films are analyzed by Rutherford Backscattering Spectroscopy, X-Ray Diffraction and dielectric measurements on parallel plate capacitors as a function of temperature (from 100 to 420 K), frequency (from 100 Hz to 1 MHz) and static electric field (from 0 to 250 kV cm−1). The evolutions of their dielectric properties with composition are systematically compared to bulk ceramic counterparts. In both cases, a continuous crossover from classical-to-relaxor ferroelectric behavior along with a decrease of the temperature of the permittivity maximum are observed as x increases. Besides, a phase convergence region (PCR) between cubic, tetragonal, orthorhombic and rhombohedral symmetries is evidenced for compositions close to x = 0.12. This is the first time that such a PCR is observed in thin films. At this point in the phase diagram, all of the dielectric parameters undergo specific variations. In particular, the enhanced permittivity dependence to external electric field for these Ca and Zr contents is attributed to an emerging relaxor behavior together with its vicinity of the PCR. These results make BCTZ thin films potential candidates to achieve electrically tunable devices.

Published
2018
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4. Nonlinear piezoelectric properties of epitaxial BaTiO3 thin film

Author

Joe Sakai, Natalia Alyabyeva, Antoine Ruyter, Jérôme Wolfman, Maxime Bavencoffe, Christophe Daumont, B. Negulescu, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)

Subjects
010302 applied physics, Materials science, business.industry, Nanogenerator, 02 engineering and technology, Laser Doppler velocimetry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Epitaxy, 01 natural sciences, Ferroelectricity, Piezoelectricity, Electronic, Optical and Magnetic Materials, Nonlinear system, 0103 physical sciences, Optoelectronics, Thin film, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 0210 nano-technology, business, ComputingMilieux_MISCELLANEOUS
Abstract

The piezoelectric properties of epitaxial BaTiO3 film were studied by double laser Doppler vibrometry. As expected for a ferroelectric material, the piezoelectric response of the structure ...

Published
2017
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5. Laser fluence and spot size effect on compositional and structural properties of BiFeO 3 thin films grown by Pulsed Laser Deposition

Author

Houssny Bouyanfif, Blandine Courtois, Christophe Daumont, B. Negulescu, Nazir Jaber, Jérôme Wolfman, Cécile Autret-Lambert, Thierry Sauvage, François Gervais, Antoine Ruyter, J.L. Longuet, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Université de Tours (UT)-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Université d'Orléans (UO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), CEA Le Ripault (CEA Le Ripault), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université de Tours-Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO)

Subjects
WDS film analysis, Materials science, Analytical chemistry, Pulsed laser deposition, Crystal growth, 02 engineering and technology, Epitaxy, 01 natural sciences, Fluence, law.invention, Lattice constant, law, 0103 physical sciences, Materials Chemistry, Oxide thin film, Thin film, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], ComputingMilieux_MISCELLANEOUS, 010302 applied physics, [PHYS]Physics [physics], Excimer laser, Metals and Alloys, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Laser, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Surface coating, BiFeO3, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology
Abstract

International audience; We investigated the effect of laser fluence and spot size on the structure and composition of BiFeO3 (BFO) epitaxial thin films grown on SrTiO3 substrates by Pulsed Laser Deposition. X-ray diffraction shows that BFO's out of plane lattice parameter increases with the laser fluence. A coherent epitaxial film growth is observed for all tested laser fluences and spot sizes for thicknesses up to 16 nm. The critical thickness at which relaxation occurs depends either on the laser fluence or spot size. The fluence dependence of the out of plane lattice parameter is accompanied with a cationic composition variation. Bi vacancies are evidenced at lower fluences while as Bi/Fe tends towards 1 a higher relaxation critical thickness is observed. An optimum Bi/Fe ratio is obtained for a fluence of 1.72 J/cm2. This result was confirmed by wavelength-dispersive x-ray spectroscopy (WDS) scans over a 1 cm2 film. An excellent thickness and composition uniformity is attained over the entire sample area

Published
2017
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6. Flexible Organic/Inorganic Hybrid Field-Effect Transistors with High Performance and Operational Stability

Author

Giorgia Franzò, Daniel Alquier, Christophe Daumont, Nicolas Camara, Abhishek Singh Dahiya, Guylaine Poulin-Vittrant, Salvo Mirabella, Charles Opoku, E. G. Barbagiovanni, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Catania [Catania], MATIS IMM CNR, and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Nanostructure, Photoluminescence, nanosheets, Zinc oxide, nanosheets, organic/inorganic hybrid, field-effect transistors, flexible substrates, flexible substrates, Nanotechnology, Context (language use), 02 engineering and technology, 010402 general chemistry, 01 natural sciences, 7. Clean energy, law.invention, law, Zinc oxide, General Materials Science, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Transistor, field-effect transistors, 021001 nanoscience & nanotechnology, Flexible electronics, 0104 chemical sciences, Transmission electron microscopy, organic / inorganic hybrid, Sapphire, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Field-effect transistor, 0210 nano-technology, organic/inorganic hybrid
Abstract

International audience; The production of high-quality semiconducting nanostructures with optimized electrical, optical, and electromechanical properties is important for the advancement of next-generation technologies. In this context, we herein report on highly obliquely aligned single-crystalline zinc oxide nanosheets (ZnO NSs) grown via the vapor−liquid−solid approach using r-plane (01−12) sapphire as the template surface. The high structural and optical quality of as-grown ZnO NSs has been confirmed using high-resolution transmission electron microscopy and temperature-dependent photoluminescence, respectively. To assess the potential of our NSs as effective building materials in high-performance flexible electronics, we fabricate organic (parylene C)/inorganic (ZnO NS) hybrid field-effect transistor (FET) devices on flexible substrates using room-temperature assembly processes. Extraction of key FET performance parameters suggests that as-grown ZnO NSs can successfully function as excellent n-type semiconducting modules. Such devices are found to consistently show very high on-state currents (Ion) > 40 μA, high field-effect mobility (μeff) > 200 cm2/(V s), exceptionally high on/off current modulation ratio (Ion/off) of around 10^9, steep subthreshold swing (s-s) < 200 mV/decade, very low hysteresis, and negligible threshold voltage shifts with prolonged electrical stressing (up to 340 min). The present study delivers a concept of integrating high-quality ZnO NS as active semiconducting elements in flexible electronic circuits.

Published
2016
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7. Cyclable and non-volatile electric field control of magnetism in BiFeO3 based magnetoelectric heterostructures

Author

B. Negulescu, Cécile Autret-Lambert, Christophe Daumont, Pascal Andreazza, Jérôme Wolfman, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Physics and Astronomy (miscellaneous), Condensed matter physics, Magnetism, Poling, Magnetoelectric effect, 02 engineering and technology, Coercivity, 021001 nanoscience & nanotechnology, 01 natural sciences, Ferroelectricity, Ferromagnetism, Remanence, Electric field, 0103 physical sciences, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

Room temperature manipulation of the ferromagnetic state via an electric field is investigated in Ni/BiFe0.95Mn0.05O3 thin film heterostructures. A 600% increase in the magnetic coercive field of the Ni layer is observed at the initial DC electrical poling of the ferroelectric BiFe0.95Mn0.05O3 layer. The magnetoelectric effect is remanent, and the magnetic coercive field can be modulated between a low value and a high value by successively switching the ferroelectric polarization. After the initial poling, the coercive field difference is decreased by subsequent back and forth switching. However, the magnetic bi-stability is preserved at least up to 250 cycles, which is promising for spintronic applications.

Published
2018
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8. Epitaxial TbMnO3 thin films on SrTiO3 substrates

Author

J.Th.M. De Hosson, Bart J. Kooi, Christophe Daumont, Diego Rubi, Sriram Venkatesan, Beatriz Noheda, D. Mannix, Gustau Catalan, and Zernike Institute for Advanced Materials

Subjects
Condensed Matter - Materials Science, Materials science, MULTIFERROICS, POLARIZATION, Condensed matter physics, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Condensed Matter Physics, Microstructure, Ferroelectricity, Tetragonal crystal system, Condensed Matter::Materials Science, Lattice constant, Ferromagnetism, PEROVSKITES, Condensed Matter::Superconductivity, General Materials Science, Orthorhombic crystal system, Condensed Matter::Strongly Correlated Electrons, ddc:530, Thin film, DEPOSITION, Anisotropy
Abstract

TbMnO$_{3}$ films have been grown under compressive strain on (001)-oriented SrTiO$_{3}$ crystals. They have an orthorhombic structure and display the (001) orientation. With increasing thickness, the structure evolves from a more symmetric (tetragonal) to a less symmetric (bulk-like orthorhombic) structure, while keeping constant the in-plane compression thereby leaving the out-of-plane lattice spacing unchanged. The domain microstructure of the films is also revealed, showing an increasing number of orthorhombic domains as the thickness is decreased: we directly observe ferroelastic domains as narrow as 4nm. The high density of domain walls may explain the induced ferromagnetism observed in the films, while both the decreased anisotropy and the small size of the domains could account for the absence of a ferroelectric spin spiral phase., Comment: Revtex, 7 pages, two columns, 10 color figures Final version as accepted for publication in Journal of Physics: Condensed Matter-Fast track communication. Role of microstructure emphasized. Main changes: Abstract and concluding remarks modified; new Discussion section added; figure on XPS measurements removed and its analysis streamlined in experimental section

Published
2009
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9. Fabrication of high performance field-effect transistors and practical Schottky contacts using hydrothermal ZnO nanowires

Author

Charles Opoku, Guylaine Poulin-Vittrant, Frédéric Cayrel, Christopher Oshman, Daniel Alquier, Christophe Daumont, Nicolas Camara, Abhishek Singh Dahiya, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours-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), Micro électronique, Composants, Systèmes, Efficacité Energétique (M@CSEE), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Electron mobility, Materials science, Fabrication, business.industry, Mechanical Engineering, Schottky diode, Bioengineering, Nanotechnology, General Chemistry, 7. Clean energy, Subthreshold slope, Hydrothermal circulation, Mechanics of Materials, Piezotronics, Optoelectronics, General Materials Science, Field-effect transistor, Electrical and Electronic Engineering, business, Temperature coefficient
Abstract

International audience; The production of large quantities of single crystalline semiconducting ZnO nanowires (NWs) at low cost can offer practical solutions to realizing several novel electronic/optoelectronic and sensor applications on an industrial scale. The present work demonstrates high-density single crystalline NWs synthesized by a multiple cycle hydrothermal process at ~100 °C. The high carrier concentration in such ZnO NWs is greatly suppressed by a simple low cost thermal annealing step in ambient air at ~450 °C. Single ZnO NW FETs incorporating these modified NWs are characterized, revealing strong metal work function-dependent charge transport, unobtainable with as-grown hydrothermal ZnO NWs. Single ZnO NW FETs with Al as source and drain (s/d) contacts show excellent performance metrics, including low off-state currents (fA range), high on/off ratio (105–107), steep subthreshold slope (

Published
2015
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10. Enhancement of piezoelectric response in Ga doped BiFeO 3 epitaxial thin films

Author

Blandine Courtois, B. Negulescu, Houssny Bouyanfif, J. Fortineau, Nazir Jaber, Jérôme Wolfman, Christophe Daumont, J.L. Longuet, Guy Feuillard, Maxime Bavencoffe, Antoine Ruyter, Cécile Autret-Lambert, Thierry Sauvage, François Gervais, GREMAN (matériaux, microélectronique, acoustique et nanotechnologies) (GREMAN - UMR 7347), Institut National des Sciences Appliquées - Centre Val de Loire (INSA CVL), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Tours-Centre National de la Recherche Scientifique (CNRS), and Université d'Orléans (UO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Piezoelectric coefficient, Materials science, Doping, Epitaxial thin film, Analytical chemistry, General Physics and Astronomy, chemistry.chemical_element, Piezoelectricity, Ferroelectricity, Piezoelectric thin films, chemistry, Ferroelectric thin films, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Gallium, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], ComputingMilieux_MISCELLANEOUS
Abstract

The piezoelectric properties of compositional spread (1 − x)BiFeO3-xGaFeO3 epitaxial thin films are investigated where Ga3+ substitution for Bi3+ is attempted in Bi1−xGaxFeO3 compounds. Ga content x was varied from 0 to 12% (atomic). Ferroelectric characterizations are reported at various length scales. Around 6.5% of Ga content, an enhancement of the effective piezoelectric coefficient d33eff is observed together with a change of symmetry of the film. Measured d33eff values in 135 nm thick films increased from 25 pm/V for undoped BiFeO3 to 55 pm/V for 6.5% Ga with no extrinsic contribution from ferroelastic domain rearrangement.

Published
2015
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11. Multifunctional tunable and piezoelectric Ba1-xCaxTi1-yZryO3 thin film capacitors

Author

Quentin Simon, Christophe Daumont, J.L. Longuet, Sandrine Payan, Jérôme Wolfman, M. Maglione, and B. Negulescu

Subjects
Capacitor, Film capacitor, Materials science, Renewable Energy, Sustainability and the Environment, business.industry, law, Energy Engineering and Power Technology, Optoelectronics, Electrical and Electronic Engineering, Thin film, business, Piezoelectricity, law.invention
Published
2016
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12. Control of ferroelectricity and magnetism in multi-ferroic BiFeO3 by epitaxial strain

Author

Laurent Bellaiche, Stéphane Fusil, Manuel Bibes, Sergey Prosandeev, Wei Ren, B. Dkhil, D. Rahmedov, Alain Barthélémy, Daniel Sando, Jean Juraszek, A. Agbelele, Ingrid C. Infante, M. Cazayous, J.M. Le Breton, C. Carrétéro, Sergey Lisenkov, Sylvain Petit, Eric Jacquet, Christophe Daumont, Unité mixte de physique CNRS/Thalès (UMP CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), Groupe de physique des matériaux (GPM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Department of Physics Department [Fayetteville], University of Arkansas [Fayetteville], Laboratoire Structures, Propriétés et Modélisation des solides (SPMS), CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Department of Physics, University of South Florida (USF), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Laboratoire Matériaux et Phénomènes Quantiques (MPQ (UMR_7162)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), Centre National de la Recherche Scientifique (CNRS)-THALES, Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Institut de Chimie du CNRS (INC)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), University of South Florida [Tampa] (USF), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Condensed matter physics, Magnetism, General Mathematics, General Engineering, General Physics and Astronomy, Nanotechnology, Articles, Ferroelectricity, chemistry.chemical_compound, Strain engineering, chemistry, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Curie temperature, Antiferromagnetism, Multiferroics, Néel temperature, Bismuth ferrite
Abstract

Recently, strain engineering has been shown to be a powerful and flexible means of tailoring the properties of ABO 3 perovskite thin films. The effect of epitaxial strain on the structure of the perovskite unit cell can induce a host of interesting effects, these arising from either polar cation shifts or rotation of the oxygen octahedra, or both. In the multi-ferroic perovskite bismuth ferrite (BiFeO 3 –BFO), both degrees of freedom exist, and thus a complex behaviour may be expected as one plays with epitaxial strain. In this paper, we review our results on the role of strain on the ferroic transition temperatures and ferroic order parameters. We find that, while the Néel temperature is almost unchanged by strain, the ferroelectric Curie temperature strongly decreases as strain increases in both the tensile and compressive ranges. Also unexpected is the very weak influence of strain on the ferroelectric polarization value. Using effective Hamiltonian calculations, we show that these peculiar behaviours arise from the competition between antiferrodistortive and polar instabilities. Finally, we present results on the magnetic order: while the cycloidal spin modulation present in the bulk survives in weakly strained films, it is destroyed at large strain and replaced by pseudo-collinear antiferromagnetic ordering. We discuss the origin of this effect and give perspectives for devices based on strain-engineered BiFeO 3 .

Published
2014
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13. Artificial chemical and magnetic structure at the domain walls of an epitaxial oxide

Author

Sriram Venkatesan, Jorge Íñiguez, César Magén, Alexander Müller, C. de Graaf, Maxim Mostovoy, Beatriz Noheda, Diego Rubi, Markus Döblinger, Christina Scheu, S. Farokhipoor, Etienne Snoeck, Christophe Daumont, University of Groningen [Groningen], Universidad de Zaragossa, Ludwig-Maximilians-Universität München (LMU), Institut de Ciència de Materials de Barcelona (ICMAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), 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)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Wageningen University and Research [Wageningen] (WUR), OncoRay - National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, TU Dresden, Condensed Matter Physics, Vrije Universiteit Brussel (VUB), Química Física i Inorgànica, Universitat Rovira i Virgili., 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)-Centre National de la Recherche Scientifique (CNRS), Theory of Condensed Matter, Zernike Institute for Advanced Materials, and Solid State Materials for Electronics

Subjects
POLARIZATION, Magnetism, molecular electronics, Ciencias Físicas, magnetic field, SQUARE-PLANAR, MANGANESE(II), FERROMAGNETISM, chemistry.chemical_compound, Strain engineering, magnetometry, HETEROSTRUCTURES, strontium, MANGANITES, perovskite, [PHYS]Physics [physics], Multidisciplinary, electron energy loss spectroscopy, nanotechnology, Ferroelectricity, Domain wall (magnetism), PEROVSKITES, Strontium titanate, scanning transmission electron microscopy, COMPLEXES, nanomaterial, CIENCIAS NATURALES Y EXACTAS, chemical reaction, Materials science, Nanotechnology, FERROELECTRICITY, AUGMENTED-WAVE METHOD, Article, THIN-FILMS, THIN FILMS, chemical composition, Multiferroics, controlled study, DOMAIN WALLS, symmetry, Thin layers, physicochemical property, crystal property, Astronomía, chemistry, Ferromagnetism, magnetism, chemical structure, PERTURBATION-THEORY, oxide
Abstract

Progress in nanotechnology requires new approaches to materials synthesis that make it possible to control material functionality down to the smallest scales. An objective of materials research is to achieve enhanced control over the physical properties of materials such as ferromagnets1, ferroelectrics2 and superconductors3. In this context, complex oxides and inorganic perovskites are attractive because slight adjustments of their atomic structures can produce large physical responses and result in multiple functionalities4,5. In addition, these materials often contain ferroelastic domains6. The intrinsic symmetry breaking that takes place at the domain walls can induce properties absent from the domains themselves7, such as magnetic or ferroelectric order and other functionalities, as well as coupling between them. Moreover, large domain wall densities create intense strain gradients, which can also affect the material’s properties8,9. Here we show that, owing to large local stresses, domain walls can promote the formation of unusual phases. In this sense, the domain walls can function as nanoscale chemical reactors. We synthesize a two-dimensional ferromagnetic phase at the domain walls of the orthorhombic perovskite terbium manganite (TbMnO3), which was grown in thin layers under epitaxial strain on strontium titanate (SrTiO3) substrates. This phase is yet to be created by standard chemical routes. The density of the two-dimensional sheets can be tuned by changing the film thickness or the substrate lattice parameter (that is, the epitaxial strain), and the distance between sheets can be made as small as 5 nanometres in ultrathin films10, such that the new phase at domain walls represents up to 25 per cent of the film volume. The general concept of using domain walls of epitaxial oxides to promote the formation of unusual phases may be applicable to other materials systems, thus giving access to new classes of nanoscale materials for applications in nanoelectronics and spintronics. Fil: Farokhipoor, S.. University of Groningen; Países Bajos Fil: Magén, C.. Universidad de Zaragoza; España Fil: Venkatesan, S.. Technische Universitat Munchen; Alemania. Universite de Tours; Francia. Gerencia de Investigación y Aplicaciones; Argentina. Instituto de Nanociencias y Nanotecnología; Argentina Fil: Íñiguez, J.. Consejo Superior de Investigaciones Científicas; España Fil: Daumont, C.J.M.. University of Groningen; Países Bajos. Universite de Tours; Francia. Gerencia de Investigación y Aplicaciones; Argentina. Instituto de Nanociencias y Nanotecnología; Argentina Fil: Rubi, Diego. University of Groningen; Países Bajos. Universite de Tours; Francia. Gerencia de Investigación y Aplicaciones; Argentina. Instituto de Nanociencias y Nanotecnología; Argentina Fil: Snoeck, E.. Universidad de Zaragoza; España Fil: Mostovoy, M.. University of Groningen; Países Bajos Fil: De Graaf, C.. University of Groningen; Países Bajos. Universitat Rovira I Virgili; España. Institució Catalana de Recerca i Estudis Avançats. Barcelona; España Fil: Müller, A.. Technische Universitat Munchen; Alemania. Universite de Tours; Francia. Gerencia de Investigación y Aplicaciones; Argentina. Instituto de Nanociencias y Nanotecnología; Argentina Fil: Döblinger, M.. Technische Universitat Munchen; Alemania Fil: Scheu, C.. Technische Universitat Munchen; Alemania. Universite de Tours; Francia. Gerencia de Investigación y Aplicaciones; Argentina. Instituto de Nanociencias y Nanotecnología; Argentina Fil: Noheda, B.. University of Groningen; Países Bajos

Published
2014
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14. Poster: Spin-Related Phenomena

Author

Honore Djieutedjeu, Kulugammana G. S. Ranmohotti, Nathan J. Takas, Julien P. A. Makongo, Xiaoyuan Zhou, Ctirad Uher, N. Haldolaarachchige, D. P. Young, Pierre F. P. Poudeu, O. Kirilmaz, M. Paul, A. Müller, D. Kufer, M. Sing, R. Claessen, S. Brück, C. Praetorius, K. Fauth, M. Kamp, P. Audehm, E. Goering, J. Verbeeck, H. Tian, G. Van Tendeloo, N. J. C. Ingle, M. Przybylski, M. Gorgoi, Bernal Iván, Gallego Silvia, Vikas Kashid, Vaishali Shah, H. G. Salunke, Y. Mokrousov, S. Blügel, Dirk Fuchs, Michael Merz, Levin Dieterle, Stefan Uebe, Peter Nagel, Stefan Schuppler, Dagmar Gerthsen, Hilbert von Löhneysen, Yoshihiko Togawa, Tsukasa Koyama, Shigeo Mori, Yusuke Kousaka, Jun Akimitsu, Sadafumi Nishihara, Katsuya Inoue, Alexander Ovchinnikov, Jun-Ichiro Kishine, Ramanathan Mahendiran, Y. Xiao, Y. Su, S. Nandi, S. Price, Th. Brückel, B. Zimmermann, P. Mavropoulos, S. Heers, N. H. Long, Ersoy Sasioglu, Christoph Friedrich, Stefan Blügel, V. Moshnyaga, Christian Binek, Xi He, Yi Wang, N. Wu, Aleksander L. Wysocki, Takashi Komesu, Uday Lanke, Anthony N. Caruso, Elio Vescovo, Kirill D. Belashchenko, Peter A. Dowben, Daniel Sando, Arsène Agbelele, Christophe Daumont, Jean Juraszek, Maximilien Cazayous, Ingrid Infante, Wei Ren, Sergey Lisenkov, Cécile Carretero, Laurent Bellaiche, Brahim Dkhil, Agnès Barthélémy, Manuel Bibes, Xianzhong Zhou, Julius Mennig, Frank Matthes, Daniel E. Bürgler, Claus M. Schneider, Anja Herpers, Chanwoo Park, Ricardo Egoavil, Jo Verbeeck, Regina Dittmann, A. I. Kurbakov, I. A. Abdel-Latif, V. A. Trunov, H. U. Habermeier, A. Al-Hajry, A. L. Malyshev, V. A. Ulyanov, J. Kishine, A. S. Ovchinnikov, I. V. Proskurin, T. Saltzmann, S. Rieß, J. Kampmeier, G. Mussler, T. Stoica, B. Kardynal, U. Simon, H. Hardtdegen, C. Felser, L. Müchler, S. Chadov, B. Yan, J. Kübler, HJ Zhang, SC Zhang, Christian Pauly, Gustav Bihlmayer, Marcus Liebmann, Martin Grob, Alexander Georgi, Dinesh Subramaniam, Markus Scholz, Jaime Sánchez-Barriga, Andrei Varykhalov, Oliver Rader, Markus Morgenstern, Irene Aguilera, Konstantin Z. Rushchanskii, Felipe Garcia-Sanchez, Riccardo Hertel, Marjana Ležaić, Veronica Goian, Stanislav Kamba, Christelle Kadlec, Petr Kužel, Roman V. Pisarev, C. R. Foschini, F. Moura, M. A. Ramirez, J. A. Varela, E. Longo, A. Z. Simões, Diana Iusan, Kunihiko Yamauchi, Kris Delaney, Silvia Picozzi, Jian Yu, Linlin Zhang, Xianbo Hou, Lluís. Yedra, Sònia Estradé, Eva. Pellicer, Moisés Cabo, Alberto López-Ortega, Marta Estrader, Josep Nogués, Dolors Baró, Zineb Saghi, Paul A. Midgley, Francesca Peiró, Timo Schena, and Bernd Zimmermann

Subjects
Colossal magnetoresistance, Materials science, Condensed matter physics, 0103 physical sciences, 010306 general physics, 01 natural sciences, 010305 fluids & plasmas, Spin-½
Published
2013
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15. Characterization of FeAIN Thin Films with Nano Sized Particles

Author

Caspar J. McConville, Xingwu Wang, Peter Lubitz, R. E. Miller, Yuandan Liu, Kevin C. Mooney, Erik Pavlina, Christophe Daumont, Robert W. Gray, and Jeffrey L. Helfer

Subjects
Materials science, Condensed matter physics, Nanotechnology, Thin film, Sputter deposition, Nano sized, Characterization (materials science)
Published
2012
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16. Strain dependence of polarization and piezoelectric response in epitaxial BiFeO3 thin films

Author

Grégory Geneste, J. Allibe, C. Carrétéro, T. Bouvet, Sergey Prosandeev, Ingrid C. Infante, Brahim Dkhil, F. Bouamrane, Sergey Lisenkov, Christophe Daumont, Eric Jacquet, Wei Ren, A. Barthélémy, Stéphane Fusil, Manuel Bibes, Laurent Bellaiche, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Department of Physics Department [Fayetteville], University of Arkansas [Fayetteville], Laboratoire Structures, Propriétés et Modélisation des solides (SPMS), Institut de Chimie du CNRS (INC)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Department of Physics, University of South Florida [Tampa] (USF), Département de Physique et Modélisation (DPM), Université d'Évry-Val-d'Essonne (UEVE), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Centre National de la Recherche Scientifique (CNRS)-THALES

Subjects
Piezoelectric coefficient, Materials science, Condensed matter physics, Transition temperature, 02 engineering and technology, Dielectric, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Piezoelectricity, Ferroelectricity, Nuclear magnetic resonance, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Curie temperature, General Materials Science, Multiferroics, Thin film, 010306 general physics, 0210 nano-technology
Abstract

International audience; Epitaxial strain has recently emerged as a powerful means to engineer the properties of ferroelectric thin films, for instance to enhance the ferroelectric Curie temperature (TC) in BaTiO3. However, in multiferroic BiFeO3 thin films an unanticipated strain-driven decrease of TC was reported and ascribed to the peculiar competition between polar and antiferrodistortive instabilities. Here, we report a systematic characterization of the room-temperature ferroelectric and piezoelectric properties for strain levels ranging between 2.5% and C1%. We find that polarization and the piezoelectric coefficient increase by about 20% and 250%, respectively, in this strain range. These trends are well reproduced by first-principles-based techniques.

Published
2012
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17. Room temperature electrical manipulation of giant magnetoresistance in spin valves exchange-biased with BiFeO3

Author

Eric Jacquet, Christophe Daumont, Stéphane Fusil, Manuel Bibes, Agnès Barthélémy, Cyrille Deranlot, J. Allibe, Daniel Sando, and Karim Bouzehouane

Subjects
Materials science, Macromolecular Substances, Surface Properties, Spin valve, Molecular Conformation, Bioengineering, Giant magnetoresistance, Reversible process, Ferric Compounds, Magnetics, Electromagnetic Fields, Materials Testing, General Materials Science, Multiferroics, Particle Size, Spin-½, Condensed matter physics, Spintronics, Mechanical Engineering, Temperature, Heterojunction, General Chemistry, Condensed Matter Physics, Nanostructures, Exchange bias, Bismuth
Abstract

Magnetoelectric multiferroics are attractive materials for the development of low-power electrically controlled spintronic devices. Here we report the optimization of the exchange bias as well as the giant magnetoresistance effect (GMR) of spin valves deposited on top of BiFeO(3)-based heterostructures. We show that the exchange bias can be electrically controlled through a change in the relative proportion of 109° domain walls and propose solutions toward a reversible process.

Published
2012

18. Long-range order of Ni2+ and Mn4+ and ferromagnetism in multiferroic (Bi0.9La0.1)(2)NiMnO6 thin films

Author

J. M. Rebled, M.V. García-Cuenca, J. Ventura, F. Peiró, Josep Fontcuberta, Sònia Estradé, C. Ferrater, Eric Langenberg, Maria Varela, Christophe Daumont, Beatriz Noheda, L.E. Coy, M.C. Polo, Zernike Institute for Advanced Materials, and Solid State Materials for Electronics

Subjects
Materials science, Condensed matter physics, Magnetoresistance, PULSED-LASER DEPOSITION, General Physics and Astronomy, Synchrotron radiation, Pulsed laser deposition, Nuclear magnetic resonance, Ferromagnetism, MAGNETORESISTANCE, Multiferroics, Thin film, Spectroscopy, Stoichiometry
Abstract

Epitaxial thin films of biferroic (Bi1-xLax)(2)NiMnO6 have been grown on SrTiO3 (001) substrates. High resolution electron microscopy, energy-loss spectroscopy and synchrotron radiation have been used to demonstrate that, under appropriate growth conditions, stoichiometric, and fully oxidized thin films with long-range order of Ni2+ and Mn4+ ions can be obtained, despite the presence of randomly distributed dissimilar cations (Bi, La) at the A-site. This ordering leads to Ni2+-O-Mn4+ ferromagnetic interactions and its preservation in thin films is key for implementation of these biferroic materials in practical devices. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3524278]

Published
2010

19. Nanoscale domain evolution in thin films of multiferroic TbMnO3

Author

Beatriz Noheda, Sriram Venkatesan, Bart J. Kooi, Jeff Th. M. De Hosson, Christophe Daumont, Nanostructured Materials and Interfaces, and Zernike Institute for Advanced Materials

Subjects
terbium compounds, Materials science, POLARIZATION, Condensed matter physics, multiferroics, Order (ring theory), twinning, Condensed Matter Physics, electric domains, epitaxial layers, Electronic, Optical and Magnetic Materials, Orientation (vector space), Tetragonal crystal system, Transmission electron microscopy, transmission electron microscopy, WALLS, Orthorhombic crystal system, Multiferroics, Thin film, Crystal twinning, ferroelectric thin films
Abstract

Control of the domain structures in multiferroic thin films is of crucial importance in order to gain access to their functional responses. Here we report on the evolution of the nanodomain structures observed in epitaxial thin films of multiferroic ${\text{TbMnO}}_{3}$ grown on ${\text{SrTiO}}_{3}$ substrates. Thin films with thickness ranging from 2 to 140 nm were grown at 0.25 and 0.9 mbar oxygen partial pressures. Transmission electron microscopy was employed to study and understand the domain evolution. A transition from a fully coherent, highly strained, tetragonal film to a partially coherent, distorted, orthorhombic structure occurs via a transformation twinning mechanism, giving rise to four different domain orientations. Then, at larger thicknesses, a transition to the fully relaxed orthorhombic structure occurs via changes in the domain-substrate orientation relationships leading to only two domain variants. Differences have been observed in the strain relaxation behavior for films grown at different oxygen pressures. All the observations have allowed us to understand the evolution of the domain structures and to accurately explain the measured orthorhombic distortion. This mechanism can be generalized for [001]-oriented orthorhombic perovskites grown on cubic substrates with large misfit values.

Published
2009

21. Ferromagnetism and increased ionicity in epitaxially grownTbMnO3films

Author

Diego Rubi, C. de Graaf, Ria Broer, Christophe Daumont, D. Mannix, Beatriz Noheda, Zernike Institute for Advanced Materials, and Theoretical Chemistry

Subjects
terbium compounds, strontium compounds, Materials science, TRANSITION-METALS, Ab initio, FOS: Physical sciences, 02 engineering and technology, Substrate (electronics), Epitaxy, magnetic thin films, 01 natural sciences, Pulsed laser deposition, THIN-FILMS, Ab initio quantum chemistry methods, ferromagnetic materials, 0103 physical sciences, DY, Thin film, 010306 general physics, pulsed laser deposition, DISTORTION, Condensed Matter - Materials Science, Condensed matter physics, ab initio calculations, X-ray photoelectron spectra, Materials Science (cond-mat.mtrl-sci), Curie temperature, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, STATES, Ferromagnetism, 0210 nano-technology, photoemission
Abstract

Thin films of TbMnO3 have been grown on SrTiO3 substrates. The films grow under compressive strain and are only partially clamped to the substrate. This produces remarkable changes in the magnetic properties and, unlike the bulk material, the films display ferromagnetic interactions below the ordering temperature of ~40K. X-ray photoemission measurements in the films show that the Mn-3s splitting is 0.3eV larger than that of the bulk. Ab initio embedded cluster calculations yield Mn-3s splittings that are in agreement with the experiment and reveal that the larger observed values are due to a larger ionicity of the films., Comment: REVTeX, 5 two-column pages, 4 EPS figures

Published
2009
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22. Influence of strain on the electronic structure of the TbMnO3/SrTiO3 epitaxial interface

Author

Christina Scheu, Beatriz Noheda, Christophe Daumont, Sriram Venkatesan, Markus Döblinger, J.T.M. de Hosson, Bart J. Kooi, Zernike Institute for Advanced Materials, Nanostructured Materials and Interfaces, and Solid State Materials for Electronics

Subjects
terbium compounds, strontium compounds, EELS, TRANSITION-METALS, Physics and Astronomy (miscellaneous), multiferroics, Electronic structure, chemical shift, Epitaxy, epitaxial layers, galvanomagnetic effects, MINERALS, Transition metal, Scanning transmission electron microscopy, Monolayer, Multiferroics, OXIDES, Thin film, Condensed matter physics, Electron energy loss spectroscopy, scanning-transmission electron microscopy, ENERGY-LOSS SPECTROSCOPY, FIELDS, MN, Crystallography, sense organs, OXIDATION-STATES, ferroelectric thin films
Abstract

Understanding the magnetotransport properties of epitaxial strained thin films requires knowledge of the chemistry at the interface. We report on the change in Mn electronic structure at the epitaxially strained TbMnO3/SrTiO3 interface. Scanning transmission electron microscopy shows an abrupt interface with a bright contrast, indicating the presence of misfit strain. Electron energy loss spectroscopy displays a chemical shift of the Mn L-2,L-3 edge together with a high white line intensity ratio revealing a reduction in the nominal Mn oxidation state in the first 3-4 monolayers. These observations indicate misfit strain significantly changes the electronic structure at the interface. (C) 2011 American Institute of Physics. [doi:10.1063/1.3663218]

Published
2011
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