A5075945541- Rare-earth and actinide compounds
- Physics of Superconductivity and Magnetism
- Advanced Condensed Matter Physics
- Iron-based superconductors research
- High-pressure geophysics and materials
- Magnetic Properties of Alloys
- Magnetic and transport properties of perovskites and related materials
- Nuclear Materials and Properties
- Magnetic properties of thin films
- Topological Materials and Phenomena
- Solid-state spectroscopy and crystallography
- Multiferroics and related materials
- Boron and Carbon Nanomaterials Research
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Optical and Acousto-Optic Technologies
- Thermodynamic and Structural Properties of Metals and Alloys
- Radioactive element chemistry and processing
- Hydrogen Storage and Materials
- Inorganic Chemistry and Materials
- Nuclear physics research studies
- Atomic and Subatomic Physics Research
- Theoretical and Computational Physics
- Advanced Chemical Physics Studies
- Corporate Taxation and Avoidance
CEA Grenoble
2015-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2015-2024
Université Grenoble Alpes
2014-2024
Institut Nanosciences et Cryogénie
2014-2024
Institut Laue-Langevin
1997-2022
CEA Cadarache
2022
Institut de Recherche Interdisciplinaire de Grenoble
2020
Université Joseph Fourier
2010-2015
National Institute of Standards and Technology
2001
NIST Center for Neutron Research
2001
Engineering lattice thermal conductivity requires to control the heat carried by atomic vibration waves, phonons. The key parameter for quantifying it is phonon lifetime, limiting travelling distance, whose determination however at limits of instrumental capabilities. Here, we show achievement a direct quantitative measurement lifetimes in single crystal clathrate Ba7.81Ge40.67Au5.33, renowned its puzzling 'glass-like' conductivity. Surprisingly, transport dominated acoustic phonons with...
Simultaneous neutron scattering and thermal expansion measurements on the heavy-fermion superconductor ${\text{URu}}_{2}{\text{Si}}_{2}$ under hydrostatic pressure of 0.67 GPa have been performed in order to detect successive paramagnetic, hidden order, large moment antiferromagnetic phases cooling. The temperature dependence sharp low energy excitation at wave vector ${\mathbf{Q}}_{\mathbf{0}}=(1,0,0)$ shows clearly that this resonance is a signature state. In phase, disappears. higher...
We report on the synthesis of superconducting single crystals FeSe, and their characterization by X-ray diffraction, magnetization resistivity. have performed ac susceptibility measurements under high pressure in a hydrostatic liquid argon medium up to 14 GPa we find that TC increases 33-36 K all samples, but with slightly different dependences samples. Above 12 no traces superconductivity are found any sample. also room temperature diffraction study powder sample, between 8.5 GPa,...
We have measured the magnetic field dependence of ordered antiferromagnetic moment and excitations in heavy-fermion superconductor URu2Si2 for fields up to 17 T applied along tetragonal c axis, using neutron scattering. The decrease intensity tiny with increasing does not follow a simple power law, but shows clear inflection point, indicating that disappears first at metamagnetic transition approximately 40 T. This suggests m is connected hidden order parameter psi which belongs same...
New inelastic neutron scattering experiments have been performed on URu2Si2 with special focus the response at Q0=(1,0,0), which is a clear signature of hidden order (HO) phase compound. With polarized experiments, it clearly shown that below HO temperature (T0 = 17.8 K) collective excitation (the magnetic resonance E0 \approx 1.7 meV) as well continuum co-exist. Careful measurements dependence lead to observation its position shifts abruptly in an activation law governed by partial gap...
Abstract The phase of the quantum-mechanical wave function can encode a topological structure with wide-ranging physical consequences, such as anomalous transport effects and existence edge states robust against perturbations. While this has been exhaustively demonstrated for electrons, properties associated elementary quasiparticles in magnetic materials are still underexplored. Here, we show theoretically via inelastic neutron scattering experiments that bulk ferromagnet Mn 5 Ge 3 hosts...
URu2Si2 is one of the most enigmatic strongly-correlated-electron systems and offers a fertile testing ground for new concepts in condensed matter science. In spite >30 years intense research, no consensus on order parameter its low-temperature hidden-order phase exists. A strong magnetic field transforms hidden into magnetically-ordered phases, whose has also been defying experimental observation. Here, thanks to an instrumentation breakthrough high-field neutron scattering, we identify...
We report a single-crystal neutron diffraction and inelastic scattering study on the spin 1/2 cuprate Cu$_3$Bi(SeO$_3$)$_2$O$_2$Cl, complemented by dielectric electric polarization measurements. The clarifies number of open issues concerning this complex material, whose frustrated interactions kagome-like lattice, combined with Dzyaloshinskii-Moriya interactions, are expected to stabilize an exotic canted antiferromagnetic order. In particular, we determine nature structural transition...
High-Entropy Alloys (HEAs) are a new family of crystalline random alloys with four or more elements in simple unit cell, at the forefront materials research for their exceptional mechanical properties. Their strong chemical disorder leads to mass and force-constant fluctuations which expected strongly reduce phonon lifetime, responsible thermal transport, similarly glasses. Still, long range order would associate HEAs crystals complex disordered cell. These two families materials, however,...
We use inelastic neutron scattering to study the low-energy spin excitations of 112-type iron pnictide ${\mathrm{Ca}}_{0.82}{\mathrm{La}}_{0.18}{\mathrm{Fe}}_{0.96}{\mathrm{Ni}}_{0.04}{\text{As}}_{2}$ with bulk superconductivity below ${T}_{c}=22\text{ }\text{ }\mathrm{K}$. A two-dimensional resonance mode is found around $E=11\text{ }\mathrm{meV}$, where energy almost temperature independent and linearly scales ${T}_{c}$ along other iron-based superconductors. Polarized analysis reveals...
The coupling of spin, charge and lattice degrees freedom results in the emergence novel states matter across many classes strongly correlated electron materials. A model example is unconventional superconductivity, which widely believed to arise from electrons via spin excitations. In cuprate high-temperature superconductors, interplay also reflected a zoo spin-density wave orders that are intertwined with superconductivity. key question whether different types density waves merely coexist...
We have performed specific-heat measurements on the heavy-fermion superconductor ${\mathrm{URu}}_{2}{\mathrm{Si}}_{2}$ in magnetic fields up to 17.5 T. A sharp peak specific heat signals antiferromagnetic transition at ${T}_{N}=17.5\mathrm{K},$ which shifts lower temperatures applied fields. In order describe below ${T}_{N},$ we used characteristic features of excitation spectrum measured by neutron scattering. The relative field dependence temperature ${T}_{N}$ and energy gap...
We report on measurements, by polarized neutron elastic scattering, of the magnetization distribution induced in a single crystal ${\mathrm{URu}}_{2}{\mathrm{Si}}_{2}$ under magnetic field applied along tetragonal $\mathbf{c}$ axis. A subtle change this distribution, revealed maximum entropy analysis data, is found when temperature decreased to range hidden order. An terms ${\mathrm{U}}^{4+}$ ionic states reveals that fingerprint freezing rank 5 multipoles, i.e., dotriacontapoles.
Resonant x-ray scattering experiments have been performed on a high-quality single crystal of URu${}_{2}$Si${}_{2}$, cut with [$101$] direction specular. Data collected at the uranium ${M}_{4}$ absorption edge below hidden-order transition temperature, ${T}_{H}=17.5$ K, exploring region reciprocal space plane [$H0L$] $1\ensuremath{\leqslant}H\ensuremath{\leqslant}1.85$ and $1.8\ensuremath{\leqslant}L\ensuremath{\leqslant}2.1$. Within sensitivity our measurements, results obtained exclude...
We report neutron diffraction measurements on $\mathrm{U}({\mathrm{Ru}}_{0.96}{\mathrm{Rh}}_{0.04}{)}_{2}{\mathrm{Si}}_{2}$ single crystal under pulsed high magnetic fields up to 30 T applied along the tetragonal $c$ axis. The high-field experiments revealed that field-induced phase II above 26 corresponds a commensurate up-up-down ferrimagnetic structure characterized by wave vector $\mathbit{q}=(2/3,0,0)$ with moments parallel axis, which naturally explains one-third magnetization plateau...
This paper is aiming to review some of the neutron scattering studies performed on URu2Si2 in Grenoble. compound has been studied for a quarter century because so-called hidden order ground state visible by most bulk experiments but almost invisible microscopic probes like neutrons, muons NMR or x-ray. We stress aspects that were not addressed previously. Firstly, comparison cell parameters 1-2-2 systems seems point magnetic properties are leading an U4+ electronic state. Secondly,...
The spin-orbit coupling (SOC) is a key to understand the magnetically driven superconductivity in iron-based superconductors, where both local and itinerant electrons are present orbital angular momentum not completely quenched. Here, we report neutron scattering study on bilayer compound CaK(Fe$_{0.96}$Ni$_{0.04}$)$_4$As$_4$ with coexisting non-collinear spin-vortex crystal magnetic order that preserves tetragonal symmetry of Fe-Fe plane. In superconducting state, two spin resonance modes...
Barium zirconate (BaZrO$_3$) is one of the very few perovskites that claimed to retain an average cubic structure down \SI{0}{\K}, while being energetically close antiferrodistortive phase obtained by condensation a soft phonon mode at R point Brillouin zone boundary. In this work, we report combined experimental and theoretical study temperature dependence mode. Inelastic neutron x-ray scattering measurements on single crystals show it softens substantially from \SI{9.4}{\meV} room...
We succeeded in growing high quality single crystals of URu2Si2 and performed thermal expansion measurements under pressure. Applying a magnetic field along the [001] direction tetragonal structure, so-called hidden-order phase reappears after suppression antiferromagnetic above critical pressure Px. determined pressure–temperature–field diagram for paramagnetic, states direction. also present temperature dependence upper Hc2 [100] by AC specific heat measurements, corresponding to bulk...
The aim of this study is to compare the magnetic behavior URu${}_{2}$Si${}_{2}$ under uniaxial stress along $a$ axis with hydrostatic pressure. Both are very similar, but presents a critical ${\ensuremath{\sigma}}_{x}^{a}$ [0.33(5) GPa] that smaller than pressure ${p}_{x}$ (0.5 GPa) where ground state switches from HO (hidden-order) AF (antiferromagnetic) state. From these values and Larmor neutron diffraction, we conclude properties governed by shortest U-U distance in plane ($a$ lattice...