ORCID Profile
0000-0002-1492-2837
Current Organisation
CNRS
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Publisher: AIP Publishing
Date: 31-05-2010
DOI: 10.1063/1.3432113
Abstract: We report on the structure and transport properties of nanocrystalline manganite La0.7Sr0.3MnO3 (LSMO) synthesized on nanowires-engineered MgO substrates by pulsed laser deposition, which is compared with reference s les deposited directly on flat MgO substrates. Such LSMO/MgO nanocomposites show enhanced low field magnetoresistance, especially at low temperature, due to the dominant spin-polarized intergrain tunneling. This work suggests that growing on nanoengineered substrates is a viable route to achieve nanostructured materials with desired crystalline structure and physical properties.
Publisher: American Chemical Society (ACS)
Date: 25-06-2015
DOI: 10.1021/ACS.NANOLETT.5B01471
Abstract: Epitaxial strain provides a powerful approach to manipulate physical properties of materials through rigid compression or extension of their chemical bonds via lattice-mismatch. Although symmetry-mismatch can lead to new physics by stabilizing novel interfacial structures, challenges in obtaining atomic-level structural information as well as lack of a suitable approach to separate it from the parasitical lattice-mismatch have limited the development of this field. Here, we present unambiguous experimental evidence that the symmetry-mismatch can be strongly controlled by dimensionality and significantly impact the collective electronic and magnetic functionalities in ultrathin perovskite LaCoO3/SrTiO3 heterojunctions. State-of-art diffraction and microscopy reveal that symmetry breaking dramatically modifies the interfacial structure of CoO6 octahedral building-blocks, resulting in expanded octahedron volume, reduced covalent screening, and stronger electron correlations. Such phenomena fundamentally alter the electronic and magnetic behaviors of LaCoO3 thin-films. We conclude that for epitaxial systems, correlation strength can be tuned by changing orbital hybridization, thus affecting the Coulomb repulsion, U, instead of by changing the band structure as the common paradigm in bulks. These results clarify the origin of magnetic ordering for epitaxial LaCoO3 and provide a route to manipulate electron correlation and magnetic functionality by orbital engineering at oxide heterojunctions.
Publisher: AIP Publishing
Date: 05-09-2011
DOI: 10.1063/1.3627182
Publisher: American Physical Society (APS)
Date: 14-10-2010
Publisher: Springer Science and Business Media LLC
Date: 11-07-2019
DOI: 10.1038/S41467-019-10961-Z
Abstract: The Rashba effect plays important roles in emerging quantum materials physics and potential spintronic applications, entailing both the spin orbit interaction (SOI) and broken inversion symmetry. In this work, we devise asymmetric oxide heterostructures of LaAlO 3 //SrTiO 3 /LaAlO 3 (LAO//STO/LAO) to study the Rashba effect in STO with an initial centrosymmetric structure, and broken inversion symmetry is created by the inequivalent bottom and top interfaces due to their opposite polar discontinuities. Furthermore, we report the observation of a transition from the cubic Rashba effect to the coexistence of linear and cubic Rashba effects in the oxide heterostructures, which is controlled by the filling of Ti orbitals. Such asymmetric oxide heterostructures with initially centrosymmetric materials provide a general strategy for tuning the Rashba SOI in artificial quantum materials.
Publisher: Wiley
Date: 20-08-2010
Publisher: American Physical Society (APS)
Date: 22-06-2015
Publisher: AIP Publishing
Date: 09-06-2008
DOI: 10.1063/1.2937843
Abstract: Leakage current behavior of (BiFeO3)m(SrTiO3)m superlattice structures was studied and analyzed at different temperatures (303–473K) in the light of various models. While bulk limited Poole–Frenkel emission was observed to dominate the leakage current in the temperature range of 303–383K, the space charge limited conduction was observed up to 473K. With a Poole–Frenkel emission type of conduction, the activation energy range of ∼0.06–0.25eV was calculated. The physical parameters, calculated from the analysis, correlate with the intrinsic properties. Such analysis of leakage current facilitates interface engineering of heterostructures for device applications.
Publisher: Springer Science and Business Media LLC
Date: 15-05-2015
DOI: 10.1038/SREP10255
Abstract: Modulation of resistance by an external magnetic field, i.e. magnetoresistance effect, has been a long-lived theme of research due to both fundamental science and device applications. Here we report colossal positive magnetoresistance (CPMR) ( ,000% at a temperature of 2 K and a magnetic field of 9 T) discovered in degenerate semiconducting strontium titanite (SrTiO 3 ) single crystals capped with ultrathin SrTiO 3 /LaAlO 3 bilayers. The low-pressure high-temperature homoepitaxial growth of several unit cells of SrTiO 3 introduces oxygen vacancies and high-mobility carriers in the bulk SrTiO 3 and the three-unit-cell LaAlO 3 capping layer passivates the surface and improves carrier mobility by suppressing surface-defect-related scattering. The coexistence of multiple types of carriers and inhomogeneous transport lead to the emergence of CPMR. This unit-cell-level surface engineering approach is promising to be generalized to others oxides and to realize devices with high-mobility carriers and interesting magnetoelectronic properties.
Publisher: American Chemical Society (ACS)
Date: 09-12-2011
DOI: 10.1021/NL2035089
Abstract: Rational synthesis of nanowires via the vapor-liquid-solid (VLS) mechanism with compositional and structural controls is vitally important for fabricating functional nanodevices from bottom up. Here, we show that branched indium tin oxide nanowires can be in situ seeded in vapor transport growth using tailored Au-Cu alloys as catalyst. Furthermore, we demonstrate that VLS synthesis gives unprecedented freedom to navigate the ternary In-Sn-O phase diagram, and a rare and bulk-unstable cubic phase can be selectively stabilized in nanowires. The stabilized cubic fluorite phase possesses an unusual almost equimolar concentration of In and Sn, forming a defect-free epitaxial interface with the conventional bixbyite phase of tin-doped indium oxide that is the most employed transparent conducting oxide. This rational methodology of selecting phases and making abrupt axial heterojunctions in nanowires presents advantages over the conventional synthesis routes, promising novel composition-modulated nanomaterials.
Publisher: American Physical Society (APS)
Date: 21-02-2013
No related grants have been discovered for Wilfrid Prellier.