A5069725572- Multiferroics and related materials
- Ferroelectric and Piezoelectric Materials
- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Dielectric properties of ceramics
- Acoustic Wave Resonator Technologies
- Nanowire Synthesis and Applications
- Microwave Dielectric Ceramics Synthesis
- Electronic and Structural Properties of Oxides
- Thermoelastic and Magnetoelastic Phenomena
- Gas Sensing Nanomaterials and Sensors
- Advanced biosensing and bioanalysis techniques
- Seismic Waves and Analysis
- Magnetic properties of thin films
- Supramolecular Self-Assembly in Materials
- Molecular Junctions and Nanostructures
- Advanced Materials Characterization Techniques
- Advanced Memory and Neural Computing
- Semiconductor materials and devices
- Semiconductor materials and interfaces
- Catalysis and Oxidation Reactions
- Ferroelectric and Negative Capacitance Devices
- Numerical methods in engineering
- Geophysical and Geoelectrical Methods
- ZnO doping and properties
Centre National de la Recherche Scientifique
2012-2021
Université de Tours
2015-2021
Institut National des Sciences Appliquées Centre Val de Loire
2018-2021
Thion Medical (France)
2018
Centre Val de Loire
2018
Laboratoire Albert Fert
2012-2014
Université Paris-Sud
2012-2014
Max Planck Society
2014
University of Groningen
2009-2014
Max Planck Innovation
2014
Magnetoelectric multiferroics are attractive materials for the development of low-power electrically controlled spintronic devices. Here we report optimization exchange bias as well giant magnetoresistance effect (GMR) spin valves deposited on top BiFeO(3)-based heterostructures. We show that can be through a change in relative proportion 109° domain walls and propose solutions toward reversible process.
Epitaxial strain has recently emerged as a powerful means to engineer the properties of ferroelectric thin films, for instance enhance Curie temperature (TC) in BaTiO3. However, multiferroic BiFeO3 films an unanticipated strain-driven decrease TC was reported and ascribed peculiar competition between polar antiferrodistortive instabilities. Here, we report systematic characterization room-temperature piezoelectric levels ranging −2.5% +1%. We find that polarization coefficient increase by...
Recent works have shown that the domain walls of room-temperature multiferroic BiFeO3 (BFO) thin films can display distinct and promising functionalities. It is thus important to understand mechanisms underlying formation in these films. High-resolution x-ray diffraction piezo-force microscopy, combined with first-principles simulations, allowed us characterize both atomic structure BFO grown under compressive strain on (001)-SrTiO3, as a function thickness. We derive twining model describes...
TbMnO(3) films have been grown under compressive strain on (001)-oriented SrTiO(3) crystals. They an orthorhombic structure and display the (001) orientation. With increasing thickness, evolves from a more symmetric (tetragonal) to less (bulk-like orthorhombic) structure, while keeping constant in-plane compression, thereby leaving out-of-plane lattice spacing unchanged. The domain microstructure of is also revealed, showing number domains as thickness decreased: we directly observe...
Thin films of ${\text{TbMnO}}_{3}$ have been grown on ${\text{SrTiO}}_{3}$ substrates. The grow under compressive strain and are only partially clamped to the substrate. This produces remarkable changes in magnetic properties and, unlike bulk material, display ferromagnetic interactions below ordering temperature $\ensuremath{\sim}40\text{ }\text{K}$. X-ray photoemission measurements show that $\text{Mn}\text{ }3s$ splitting is 0.3 eV larger than bulk. Ab initio embedded-cluster calculations...
Control of the domain structures in multiferroic thin films is crucial importance order to gain access their functional responses. Here we report on evolution nanodomain observed epitaxial ${\text{TbMnO}}_{3}$ grown ${\text{SrTiO}}_{3}$ substrates. Thin with thickness ranging from 2 140 nm were at 0.25 and 0.9 mbar oxygen partial pressures. Transmission electron microscopy was employed study understand evolution. A transition a fully coherent, highly strained, tetragonal film partially...
Recently, strain engineering has been shown to be a powerful and flexible means of tailoring the properties ABO3 perovskite thin films. The effect epitaxial on structure unit cell can induce host interesting effects, these arising from either polar cation shifts or rotation oxygen octahedra, both. In multi-ferroic bismuth ferrite (BiFeO3-BFO), both degrees freedom exist, thus complex behaviour may expected as one plays with strain. this paper, we review our results role ferroic transition...
The production of high-quality semiconducting nanostructures with optimized electrical, optical, and electromechanical properties is important for the advancement next-generation technologies. In this context, we herein report on highly obliquely aligned single-crystalline zinc oxide nanosheets (ZnO NSs) grown via vapor-liquid-solid approach using r-plane (01-12) sapphire as template surface. high structural optical quality as-grown ZnO NSs has been confirmed high-resolution transmission...
The production of large quantities 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. present work demonstrates high-density NWs synthesized by a multiple cycle hydrothermal process ∼100 °C. high carrier concentration in such is greatly suppressed simple thermal annealing step ambient air ∼450 Single NW FETs incorporating these modified are...
Tunable ferroelectric capacitors, which exhibit a decrease of the dielectric permittivity (ϵ) under electric field, are widely used in electronics for RF tunable applications (e.g., antenna impedance matching). Current devices use barium strontium titanate as dielectric, and need performance enhancement element is key device improvement. We report here on libraries Ba0.97Ca0.03Ti1−xZrxO3 thin films (0 ≤ x 27%) with thickness about 130 nm deposited IrO2/SiO2/Si substrates using combinatorial...
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 reported at various length scales. Around 6.5% content, an enhancement the effective coefficient d33eff observed together with a change symmetry film. Measured values 135 nm thick increased 25 pm/V undoped BiFeO3 55 no extrinsic...
Epitaxial thin films of biferroic (Bi1−xLax)2NiMnO6 have been grown on SrTiO3 (001) substrates. High resolution electron microscopy, energy-loss spectroscopy and synchrotron radiation used to demonstrate that, under appropriate growth conditions, stoichiometric, fully oxidized with long-range order Ni2+ Mn4+ ions can be obtained, despite the presence randomly distributed dissimilar cations (Bi, La) at A-site. This ordering leads Ni2+–O–Mn4+ ferromagnetic interactions its preservation in is...
Understanding the magnetotransport properties of epitaxial strained thin films requires knowledge chemistry at interface. We report on change in Mn electronic structure epitaxially TbMnO3/SrTiO3 Scanning transmission electron microscopy shows an abrupt interface with a bright contrast, indicating presence misfit strain. Electron energy loss spectroscopy displays chemical shift L2,3 edge together high white line intensity ratio revealing reduction nominal oxidation state first 3–4 monolayers....
Room temperature manipulation of the ferromagnetic state via an electric field is investigated in Ni/BiFe0.95Mn0.05O3 thin film heterostructures. A 600% increase magnetic coercive Ni layer observed at initial DC electrical poling ferroelectric BiFe0.95Mn0.05O3 layer. The magnetoelectric effect remanent, and can be modulated between a low value high by successively switching polarization. After poling, difference decreased subsequent back forth switching. However, bi-stability preserved least...
The piezoelectric properties of epitaxial BaTiO3 film were studied by double laser Doppler vibrometry. As expected for a ferroelectric material, the response structure is hysteretic. d33 value reduced from maximum 42 pm/V to 25 when increasing DC bias, indicating large influence extrinsic effects close coercive fields. Using Rayleigh approach, slight nonlinearity as function AC field was attributed irreversible domain wall displacements. At high electric fields strain saturates. second...
Tunable ferroelectric capacitors, which exhibit a decrease in the dielectric permittivity under an electric field, are widely used electronics for RF tunable applications. Current devices use barium strontium titanate (BST) as dielectric, but new applications call materials with specific performance improvements. It is then of crucial importance to dispose large panel electrically characterized identify most suited compound given set device specifications. Here, we report on tuning...