A5056916162- Advanced Condensed Matter Physics
- Physics of Superconductivity and Magnetism
- Magnetic and transport properties of perovskites and related materials
- Multiferroics and related materials
- Advanced NMR Techniques and Applications
- X-ray Diffraction in Crystallography
- Solid-state spectroscopy and crystallography
- Quantum, superfluid, helium dynamics
- Crystallization and Solubility Studies
- Nuclear Physics and Applications
- Spectroscopy and Quantum Chemical Studies
- Protein Structure and Dynamics
- Metal-Organic Frameworks: Synthesis and Applications
- Atomic and Subatomic Physics Research
- Magnetism in coordination complexes
- High-pressure geophysics and materials
- Material Dynamics and Properties
- Lipid Membrane Structure and Behavior
- Nuclear materials and radiation effects
- Rare-earth and actinide compounds
- Inorganic Fluorides and Related Compounds
- Nanopore and Nanochannel Transport Studies
- Cold Atom Physics and Bose-Einstein Condensates
- Methane Hydrates and Related Phenomena
- Enzyme Structure and Function
Institut Laue-Langevin
2016-2025
Institut Néel
2023-2024
Centre des Matériaux
2023-2024
Tokyo Metropolitan University
2022
Institut Langevin
2004-2021
Wallingford Public Library
2021
CEA Grenoble
2018
Centre de Coopération Internationale en Recherche Agronomique pour le Développement
2017
Centre Hospitalier Universitaire de Bordeaux
2017
Université Paris-Sud
2013
Magnetic susceptibility, NMR, muon spin relaxation, and inelastic neutron scattering measurements show that kapellasite, Cu3Zn(OH)6Cl2, a geometrically frustrated spin-1/2 kagome antiferromagnet polymorphic with herbertsmithite, is gapless liquid showing unusual dynamic short-range correlations of noncoplanar cuboc2 type which persist down to 20 mK. The Hamiltonian determined from fit high-temperature series expansion bulk susceptibility data possesses competing exchange interactions....
Abstract The water stable UiO‐66(Zr)‐(CO 2 H) MOF exhibits a superprotonic conductivity of 2.3×10 −3 S cm −1 at 90 °C and 95 % relative humidity. Quasi‐elastic neutron scattering measurements combined with aMS‐EVB3 molecular dynamics simulations were able to probe individually the both confined protons molecules further reveal that proton transport is assisted by formation hydrogen‐bonded network spans from tetrahedral octahedral cages this MOF. This first joint experimental/modeling study...
Inelastic neutron scattering, far-infrared spectroscopy, and cryogenic nuclear magnetic resonance are used to investigate the quantized rotation ortho–para conversion of single water molecules trapped inside closed fullerene cages. The existence metastable ortho -water is demonstrated, interconversion -and para spin isomers tracked in real time. Our investigation reveals that ground state encapsulated has a lifted degeneracy, associated with symmetry-breaking environment.
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...
At low temperatures, ${\mathrm{Tb}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ enters a spin liquid state, despite expectations of magnetic order and/or structural distortion. Using neutron scattering, we have discovered that in this state an excited crystal field level is coupled to transverse acoustic phonon, forming hybrid excitation. Magnetic and phononlike branches with identical dispersion relations can be identified, the hybridization vanishes paramagnetic state. We suggest aptly named...
Small-angle X-ray scattering (SAXS) and elastic quasi-elastic neutron techniques were used to investigate the high-pressure-induced changes on interactions, low-resolution structure dynamics of lysozyme in solution. SAXS data, analysed using a global-fit procedure based new approach for hydrated protein form factor description, indicate that completely maintains its globular up 1500 bar, but significant modifications protein-protein interaction potential occur at approximately 600-1000 bar....
The separation ability of branched alkane isomers ( n HEX, 3MP, 22DMB) the flexible and functionalized microporous iron(III) dicarboxylate MIL‐53(Fe)‐(CF 3 ) 2 solid is evaluated through a combination breakthrough experiments (binary or ternary mixtures), adsorption isotherms, X‐ray diffraction temperature analysis, quasi‐elastic neutron scattering measurements molecular dynamics simulations. A kinetically controlled sieve between di‐branched isomer hexane 22DMB from mixture paraffins...
Low-temperature states of polycrystalline samples a frustrated pyrochlore oxide Tb${}_{2+x}$Ti${}_{2\ensuremath{-}x}$O${}_{7+y}$ have been investigated by specific heat, magnetic susceptibility, and neutron scattering experiments. We found that this system can be tuned minute change $x$ from spin-liquid state ($x<{x}_{\text{c}}$) to partly ordered with small antiferromagnetic ordering the order $0.1{\ensuremath{\mu}}_{\text{B}}$. Specific heat shows sharp peak at phase transition...
A comprehensive study of commercially available and newly synthesized proton conducting perfluorinated sulfonic acid (PFSA) surfactants polymeric systems is reported, specially designed in a bottom-up search to improve the basic understanding PFSA polymers used as benchmark electrolytes fuel cells. Hydration-dependent mesomorphous phases are formed by self-assembly these molecules water. The impact hydrophobic chain length, density charge, molecular architecture on nanostructure, dynamics...
By applying pulsed-field gradient nuclear magnetic resonance (PFG NMR) in comparison to quasi-elastic neutron scattering (QENS), we sense by measurement of the diffusion n-octane on different length scales, transport resistances faujasite type X (which is isostructural with Y and differs lower Si/Al ratio only) mutual distances less than 300 nm. Direct observation real structure zeolite transmission electron microscopy identifies them as stacking faults mirror-twin (111)-type planes cubic...
The fully overhauled IN5 was the first cold neutron time-of-flight spectrometer equipped with position sensitive detectors. It has been in scheduled operation since end of 2008. experience use confirmed expectations terms both a qualitative and quantitative efficiency increase, allowing to open new opportunities for spectroscopy. Using full potential detectors brought up an increasing demand single crystal spectroscopy while enhanced count-rate better signal-to-noise allow studying smaller...
We investigated molecular motions in the 0.3–350 ps time range of D2O-hydrated bilayers 1-palmitoyl-oleoyl-sn-glycero-phosphocholine and 1,2-dimyristoyl-sn-glycero-phosphocholine liquid phase by quasielastic neutron scattering. Model analysis sets spectra covering scale lengths from 4.8 to 30 Å revealed presence three types motion taking place on well-separated scales: (i) slow diffusion whole phospholipid molecules a confined cylindrical region; (ii) conformational chains; (iii) fast...
We report a detailed study of the dynamics oxide ionic conduction in brownmillerite-type Sr2Fe2O5, including lattice anisotropy, based on neutron scattering studies large (partially twinned) single crystal combination with ab initio molecular simulations. Single-crystal diffraction reveals supercell peaks due to long-range ordering among chains corner-sharing FeO4 tetrahedra, which disappears heating above 540 °C confined local rotations tetrahedra. Our simulations show that these are...
The splitting of the <italic>ortho</italic>-H<sub>2</sub>O ground state is clearly revealed by inelastic neutron scattering.
Water confined within carbon nanotubes (CNT) exhibits tremendous enhanced transport properties. Here, we extend this result to ionic liquids (IL) in vertically aligned CNT membranes. Under confinement, the IL self-diffusion coefficient is increased by a factor 3 compared its bulk reference. This could lead high power battery separators.
Abstract Entanglement is a crucial resource for quantum information processing and its detection quantification of paramount importance in many areas current research. Weakly coupled molecular nanomagnets provide an ideal test bed investigating entanglement between complex spin systems. However, these systems has only been experimentally demonstrated rather indirectly by macroscopic techniques or fitting trial model Hamiltonians to experimental data. Here we show that four-dimensional...
The dynamical magnetic correlations in ${\mathrm{Tb}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ have been investigated using polarized inelastic neutron scattering. Dispersive excitations are observed, emerging from pinch points reciprocal space and characterized by an anisotropic spectral weight. Anomalies the crystal field phonon excitation spectrum at Brillouin zone centers also reported. These findings suggest that Coulomb phases, although they present a disordered ground state with dipolar...
We present an experimental study of the quantum spin ice candidate pyrochlore coumpound \przr\ by means magnetization measurements, specific heat and neutron scattering up to 12 T down 60 mK. When field is applied along $[111]$ $[1\bar{1}0]$ directions, ${\bf k}=0$ induced structures settle in. find that ordered moment rises slowly, even at very low temperature, in agreement with macroscopic magnetization. Interestingly, for $H \parallel [1\bar{1}0]$, appears on so called $\alpha$ chains...
A hidden order that emerges in the frustrated pyrochlore Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ with $T_{\text{c}}=0.53$ K is studied using specific heat, magnetization, and neutron scattering experiments on a high-quality single crystal. Semi-quantitative analyses based pseudospin-1/2 Hamiltonian for ionic non-Kramers magnetic doublets demonstrate it an ordered state of electric quadrupole moments. The elusive spin liquid nominal Tb$_2$Ti$_2$O$_7$ most likely U(1) quantum spin-liquid state.