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Karine Provost

Publications and source records attributed to Karine Provost.

2 recordsLinked to original sources
arXiv2022

Experimental investigation of the local environment and lattice distortion in refractory medium entropy alloys

EXAFS analysis of pure elements, binary and ternary equiatomic refractory alloys within the Nb-Zr-Ti-Hf-Ta system is performed at the Nb and Zr K-edges to analyze the evolution of the chemical local environment and the lattice distortion. A good mixing of the elements is found at the atomic scale. For some compounds, a distribution of distances between the central atom and its neighbors suggests a distortion of the structure. Finally, analysis of the Debye-Waller parameters show some correlation with the lattice distortion parameter $δ^2$, and allows to quantify experimentally the static disorder in medium entropy alloys.

cond-mat.mtrl-sci↗
arXiv2021

Direct and indirect magnetocaloric effects near room temperature related to structural transitions in Y$_{0.9}$Pr$_{0.1}$Fe$_2$D$_{3.5}$ deuteride

The structural and magnetic properties of Y$_{0.9}$Pr$_{0.1}$Fe$_2$D$_{3.5}$ deuteride have been investigated by synchrotron and neutron diffraction, magnetic measurements, and differential scanning calorimetry. Deuterium insertion induces a 23.5 % cell volume increase and a lowering of crystal symmetry compared to the cubic C15 parent compound (Fd-3m SG). The deuteride is monoclinic (P21/c SG) below 330 K and undergoes a first order transition between 330 and 350 K towards a pseudo-cubic structure (R-3m SG) with TO-D = 342(2) K. The compound is ferromagnetic, accompanied by a magnetostrictive effect below TC = 274 K. The analysis of the critical exponents indicates a second order type transition with a deviation from the isotropic 3D Heisenberg model towards the 3D XY model. This implies an easy plane of magnetization in agreement with cell parameter variation showing a planar magnetic orientation. A weak magnetic peak is even observed at the order-disorder transition with a maximum at 343 K. Magnetic entropy variations are characteristic of direct and reverse magnetocaloric effects at TC and TO-D respectively.

physics.app-ph↗