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Your search keyword '"J.-P. Brison"' showing total 5 results
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5 results on '"J.-P. Brison"'

1. Evidence of Fermi surface reconstruction at the metamagnetic transition of the strongly correlated superconductor UTe_{2}

Author

Q. Niu, G. Knebel, D. Braithwaite, D. Aoki, G. Lapertot, M. Vališka, G. Seyfarth, W. Knafo, T. Helm, J.-P. Brison, J. Flouquet, and A. Pourret

Subjects
Physics, QC1-999
Abstract

Thermoelectric power (S) and Hall effect (R_{H}) measurements on the paramagnetic superconductor UTe_{2} with the magnetic field applied along the hard magnetization b axis are reported. The first-order nature of the metamagnetic transition at H_{m}=H_{c2}^{b}=35 T leads to drastic consequences on S and R_{H}. In contrast to the field dependence of the specific heat in the normal state through H_{m}, S(H) is not symmetric with respect to H_{m}. This implies a strong interplay between ferromagnetic fluctuations and a Fermi-surface reconstruction at H_{m}. R_{H} is very well described by incoherent skew scattering above the coherence temperature T_{m} corresponding roughly to the temperature of the maximum in the susceptibility T_{χ_{max}} and coherent skew scattering at lower temperatures. The discontinuous field dependence of both S(H) and the ordinary Hall coefficient R_{0}, at H_{m} and at low temperature, provides evidence of a change in the band structure at the Fermi level.

Published
2020
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2. Field-Induced Tuning of the Pairing State in a Superconductor

Author

A. Rosuel, C. Marcenat, G. Knebel, T. Klein, A. Pourret, N. Marquardt, Q. Niu, S. Rousseau, A. Demuer, G. Seyfarth, G. Lapertot, D. Aoki, D. Braithwaite, J. Flouquet, and J. P. Brison

Subjects
Physics, QC1-999
Abstract

The recently discovered superconductor UTe_{2}, with a superconducting transition temperature T_{c} between 1.5 and 2 K, is attracting much attention due to strong suspicion of spin-triplet and topological superconductivity. Its properties under magnetic field are also remarkable, with field-reinforced (H∥b) and field-induced [H in the (b,c) plane] superconducting phases. Here, we report the first complete thermodynamic determination of the phase diagram for fields applied along the three crystallographic directions. For field along the easy a axis, we uncover a strong negative curvature of the upper critical field very close to T_{c}, revealing a strong suppression of the pairing strength at low magnetic fields. By contrast, measurements performed up to 36 T along the hard magnetization b axis confirm a bulk field-reinforced superconducting phase. Most of all, they also reveal the existence of a phase transition line within the superconducting phase. Drastic differences occur between the low-field and high-field phases pointing to different pairing mechanisms. Detailed analysis suggests a possible transition between a low-field spin-triplet to high-field spin-singlet state, a unique case among superconductors.

Published
2023
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3. Unconventional superconductivity in UTe

Author

D, Aoki, J-P, Brison, J, Flouquet, K, Ishida, G, Knebel, Y, Tokunaga, and Y, Yanase

Abstract

The novel spin-triplet superconductor candidate UTe

Published
2021

4. Experimental and numerical assessment of grain boundary energies in polycrystalline uranium dioxide

Author

D. Drouan, Gérard Lapertot, J.-P. Brison, A. Ksibi, A. Pena, Renaud C. Belin, Muriel Gaudet, E. Bourasseau, A. Germain, X. Iltis, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 [IEMN], Optique et Matériaux [NEEL - OPTIMA], Instrumentation, Material and Correlated Electrons Physics [IMAPEC], CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CEA Cadarache, Optique et Matériaux (NEEL - OPTIMA), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Instrumentation, Material and Correlated Electrons Physics (IMAPEC), PHotonique, ELectronique et Ingénierie QuantiqueS (PHELIQS), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), and Optique et Matériaux (OPTIMA)

Subjects
Grain boundary energy, Uranium dioxide, UO2, Grain boundaries, Groove, Thermal grooving theory, surface energy, CRG potential, Materials science, 02 engineering and technology, Dihedral angle, 01 natural sciences, Molecular physics, Molecular dynamics, chemistry.chemical_compound, 0103 physical sciences, Materials Chemistry, Ceramic, 010302 applied physics, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Tilt (optics), chemistry, visual_art, Ceramics and Composites, visual_art.visual_art_medium, Grain boundary, Crystallite, 0210 nano-technology, Electron backscatter diffraction
Abstract

International audience; Uranium dioxide ceramics are widely used as nuclear fuels. Thus, it is important to understand the role of the grain boundaries (GBs) which decisively govern the properties of these polycrystalline materials and subsequently determine their performances. Here, we report a coupled numerical-experimental approach enabling to assess GB energies. Firstly, GB formation energies (γgb) were computed for 34 symmetric tilt GBs in UO2 with molecular dynamics simulations at 1700 K. The surface energies (γS) relative to the respective planes of these GBs were calculated as well. The Herring relation was then used to assess the dihedral angles Ψ of the corresponding GB grooves. Secondly, a UO2 ceramic sample was annealed at 1673 K to obtain GB grooves. The CSL GBs of interest were identified by EBSD and their Ψ angles determined by AFM. Computed and measured Ψ values were found to be very close.

Published
2020
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5. Thermal Conductivity through the Quantum Critical Point in YbRh_{2}Si_{2} at Very Low Temperature

Author

M, Taupin, G, Knebel, T D, Matsuda, G, Lapertot, Y, Machida, K, Izawa, J-P, Brison, and J, Flouquet

Abstract

The thermal conductivity of YbRh_{2}Si_{2} has been measured down to very low temperatures under field in the basal plane. An additional channel for heat transport appears below 30 mK, both in the antiferromagnetic and paramagnetic states, respectively, below and above the critical field suppressing the magnetic order. This excludes antiferromagnetic magnons as the origin of this additional contribution to thermal conductivity. Moreover, this low temperature contribution prevails a definite conclusion on the validity or violation of the Wiedemann-Franz law at the field-induced quantum critical point.

Published
2015

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