A5053986512- Magnetic and transport properties of perovskites and related materials
- Advanced Condensed Matter Physics
- Multiferroics and related materials
- Crystallization and Solubility Studies
- Advanced Thermoelectric Materials and Devices
- Rare-earth and actinide compounds
- Nuclear Materials and Properties
- Iron-based superconductors research
- X-ray Diffraction in Crystallography
- High Entropy Alloys Studies
- Hydrogen Storage and Materials
- Chalcogenide Semiconductor Thin Films
- Inorganic Chemistry and Materials
- Magnetic Properties of Alloys
- Phase-change materials and chalcogenides
- Nuclear reactor physics and engineering
- Ferroelectric and Piezoelectric Materials
- Thermal Expansion and Ionic Conductivity
- Metal and Thin Film Mechanics
- Physics of Superconductivity and Magnetism
- X-ray Spectroscopy and Fluorescence Analysis
- Fusion materials and technologies
- Radioactive element chemistry and processing
- Electron and X-Ray Spectroscopy Techniques
- High-Temperature Coating Behaviors
Institut Néel
2016-2025
Centre National de la Recherche Scientifique
2015-2025
Université Grenoble Alpes
2015-2025
Institut Laue-Langevin
2011-2024
Institut polytechnique de Grenoble
2019
Université Joseph Fourier
2007-2017
CEA Grenoble
2006-2009
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2006-2009
European Synchrotron Radiation Facility
2006-2007
Centre de Recherche et d’Enseignement de Géosciences de l’Environnement
2007
High-performance thermoelectric bulk sulfide with the colusite structure is achieved by controlling densification process and forming short-to-medium range structural defects. A simple powerful way to adjust carrier concentration combined enhanced phonon scattering through point defects disordered regions described. By combining experiments band phonons calculations, we elucidate, for first time, underlying mechanism at origin of intrinsically low thermal conductivity in samples as well...
This paper presents a comparison between several methods dedicated to the interpretation of V K-edge X-ray absorption near-edge structure (XANES) features. XANES spectra V-bearing standard compounds were measured in an effort evaluate advantages and limits each method. The include natural minerals synthetic containing vanadium at various oxidation state (from +3 +5) different symmetry (octahedral, tetrahedral, square pyramidal). Correlations normalized pre-edge peak area its centroid...
A new set-up is reported of an indirect cryogenic cooling system for a double-crystal monochromator which runs on the BM30b/FAME beamline at ESRF (Grenoble, France). This device has been conceived to limit vibrations first diffracting crystal and maintain it constant temperature. These points are crucial maximizing stability. Moreover, relative angular position second can be dynamically adjusted by piezoelectric transducer coupled with feedback in order always maximum rocking curve during...
Extended x-ray absorption fine structure experiments at the Zr $K$ edge were carried out on perovskite relaxor ferroelectrics $\mathrm{Ba}{\mathrm{Ti}}_{1\ensuremath{-}x}{\mathrm{Zr}}_{x}{\mathrm{O}}_{3}$ (BTZ) $(x=0.25,0.30,0.35)$, and $\mathrm{Ba}\mathrm{Zr}{\mathrm{O}}_{3}$ for comparison. Structural information up to $4.5\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ around atoms is obtained, revealing that local differs notably from average $Pm\overline{3}m$ cubic deduced diffraction. In...
Abstract The introduction of hexavalent T 6+ cations in p‐type thermoelectric colusites Cu 26 2 Ge 6 S 32 ( = Cr, Mo, W) leads to the highest power factors among iono‐covalent sulfides, ranging from 1.17 mW m −1 K −2 at 700 for W a value 1.94 Cr. In Cr , ZT reaches values close unity K. improvement transport properties these new sulfides is explained on basis electronic structure and calculations keeping mind that relaxation time significantly influenced by size electronegativity...
Bornite Cu<sub>5</sub>FeS<sub>4−x</sub>Se<sub>x</sub> (0 ≤ <italic>x</italic> 0.6) compounds have been synthesized, using mechanical alloying, combined with spark plasma sintering (SPS).
Al0.10Ti0.30V0.25Zr0.10Nb0.25 was prepared to evaluate the effect of 10% aluminum into previously reported quaternary alloy, Ti0.325V0.275Zr0.125Nb0.275. The as-cast quinary alloy formed a single-phase body centered cubic solid solution and transformed tetragonal after hydrogenation. had storage capacity 1.6 H/M (2.6 wt.%) with fast absorption kinetics at room temperature, reaching full within first 10 min. major improvements Al addition (10%) were related desorption cycling properties...
A bent-crystal spectrometer based on the Rowland circle geometry has been installed and tested BM30b/FAME beamline at European Synchrotron Radiation Facility to improve its performances. The energy resolution of allows different kinds measurements be performed, including X-ray absorption spectroscopy, resonant inelastic scattering Raman experiments. simplicity experimental device makes it easily implemented a classical beamline. This improvement in fluorescence detection is particular...
Structural analysis of colusite phases by neutron diffraction pattern refinement and high resolution transmission electron microscopy.
We are reporting the synthesis, physicochemical, and hydrogen sorption properties of a novel bcc high entropy alloy Ti0.30V0.25Cr0.10Zr0.10Nb0.25. At room temperature, rapidly absorbs reaching capacity 2.0 H/M (3.0 wt.%) forming dihydride with fcc structure, as confirmed by both synchrotron X-ray diffraction neutron diffraction. The absorption Pressure–Composition Isotherms corroborated prove that reaction occurs within two steps, i.e., → monohydride dihydride. thermodynamic parameters...
Two extensively researched high-entropy alloys (HEAs) TiZrNbHfV and TiZrNbHfTa have been reported for their high hydrogen capacities yet shown different behaviors with regard to sorption properties. The first composition reacts within a one-step reaction mechanism associated phase transition from an initial body-centered cubic (BCC) lattice tetragonal (BCT) dihydride while the latter alloy undergoes two-step process BCC intermediate BCT monohydride finally face-centered (FCC) dihydride. For...
High-entropy alloys (HEAs) are a promising class of materials that can grant remarkable functional performances for large range applications due to their highly tunable composition. Among these applications, recently, bcc HEAs capable forming fcc hydrides have been proposed as high-capacity hydrogen storage with improved thermodynamics compared classical metal hydrides. In this context, single-phase (TiVNb)0.90Cr0.05Mn0.05 HEA was prepared by arc melting evaluate the effect combined Cr/Mn...
Metastable β-As2Te3 (R3̅m, a = 4.047 Å and c 29.492 at 300 K) is isostructural to layered Bi2Te3 known for similarly displaying good thermoelectric properties around 400 K. Crystallizing glassy-As2Te3 leads multiphase samples, while could indeed be synthesized with phase purity (97%) by melt quenching. As expected, reconstructively transforms into stable α-As2Te3 (C2/m, 14.337 Å, b 4.015 9.887 β 95.06°) 480 This → α transformation can seen as the displacement of part atoms from their As2Te3...
Abstract A new class of cost‐efficient n ‐type thermoelectric sulfides with a layered structure is reported, namely MnBi 4 S 7 and FeBi . Theoretical calculations combined synchrotron X‐ray/neutron diffraction analyses reveal the origin their electronic thermal properties. The complex low‐symmetry monoclinic crystal generates an band mixture heavy light bands near conduction edge, as well vibrational properties favorable for high performance. low conductivity can be attributed to existence...
The systematic presence of the ternary phases U 6 Mo 4 Al 43 and UMo 2 20 is reported in a U–Mo/Al interaction layer grown by thermal annealing. This work shows, therefore, low solubility UAl 3 binary phases; it contradicts hypothesis formation (U,Mo)Al solid solutions often admitted literature. Using µ-XAS (micro X-ray absorption spectroscopy) at K edge µ-XRD diffraction), heterogeneity obtained on γ-U 0.85 0.15 /Al diffusion couple has been precisely investigated. phase identified closest...
The crystal and magnetic structure of SmCo5 is determined by neutron powder diffraction between 5 K the Curie temperature. In order to overcome enormous absorption samarium, a 154Sm isotopically enriched sample was used. ordered moments both crystallographically distinct cobalt atoms are not significantly different over whole temperature range. They decrease from 2.2 μB at about 0.6 1029 K. Samarium's moment decreases 1.0 K, runs through minimum 0.2 around 650 becomes larger than cobalt's...
A material with broken space-inversion and time-reversal symmetries can exhibit symmetry-dependent unique phenomena such as the magnetoelectric effect. Ferroic order of magnetic quadrupoles fulfills this symmetry condition. The authors report here discovery ferroic quadrupole its activity in novel compound Pb(TiO)Cu${}_{4}$(PO${}_{4}$)${}_{4}$, which is contrast isostructural Ba(TiO)Cu${}_{4}$(PO${}_{4}$)${}_{4}$ Sr(TiO)Cu${}_{4}$(PO${}_{4}$)${}_{4}$ exhibiting antiferroic order. Their...
High-entropy alloys (HEAs) represent an interesting alloying strategy that can yield exceptional performance properties needed across a variety of technology applications, including hydrogen storage. Examples include ultrahigh volumetric capacity materials (BCC → FCC dihydrides) with improved thermodynamics relative to conventional high-capacity metal hydrides (like MgH2), but still further destabilization is reduce operating temperature and increase system-level capacity. In this work, we...