New U2T2X Hydrides

Abstract is not availableJRC.E.6-Actinides researc

Peculiarities of U2T2X hydrides

U2Ni2Sn belongs to a large group of U2T2X compounds which are very sensitive to hydrogen absorption. U2Ni2SnH1.8 and U2Ni2SnD1.8 exhibit similar magnetic behaviour they order antiferromagnetically at , which is much higher than in U2Ni2Sn. Deuterium lattice sites were determined by neutron diffraction. Uranium magnetic moments lie in the basal plane of the tetragonal structure

Structure and Magnetism of Thin UX Layers

US layers (thickness 0.1 0.3 m) were prepared by sputter deposition from US target in Ar atmosphere at temperatures 298 573 K. For US thin films, magnetism tends to be suppressed comparing to the bulk US, which is a band ferromagnet with TC = 177 K. TC decreases down to 85 105K for the layers deposited at room temperature (depending on the deposition parameters) and increases with the increase of the temperature of substrate. Spontaneous magnetization in the ordered state is suppressed considerably for the deposited layers: down to 0.1B/f.u. or less for all samples studied (compare with 1.55 B/f.u. for bulk US). The changes in the magnetic properties are correlated with the microstructure of the films. Microstructure studies indicated that the US thin films contain a mixture of “nanocrystalline” and “amorphous” parts. The crystallite size in the nanocrystalline parts is approximately 100 A . In all samples, a compressive residual stress was observed, which caused a strongly anisotropic lattice deformation with the easy deformation direction (1 1 1). The compressive residual stress was below −3GPa in most samples. Results are compared with UN layers synthesized by reactive sputtering.JRC.E.6-Actinides researc

5f magnetism studied in complex intermetallic U based hydrides

Hydrogen absorption in uranium ternary intermetallic compounds typically increases ordering temperatures and magnetic moments. The case of URuSn hydride, which does not behave accordingly, can be related to specific H positions revealed by neutron diffraction on deuterides. Tuning through the onset of magnetic ordering by means of H absorption was found for the U2T2X compounds as U2Co2Sn. For U2Ni2SnD1.8, we demonstrated that the anisotropic lattice expansion leads to U moments reorientation, as a result of hybridisation induced two ion anisotropy, with respect to U2Ni2Sn, in which the UU coordination is poised between two regimes

High-Field and High-Pressure Studies of UPdSi and UNiSi Hydrides

Abstract not availableJRC.E-Institute for Transuranium Elements (Karlsruhe

5f Magnetism Studied in Complex Intermetallic U-based Hydrides

Hydrogen absorption in uranium ternary intermetallic compounds typically increases ordering temperatures and magnetic moments. The case of URuSn hydride, which does not behave accordingly, can be related to specific H positions revealed by neutron diffraction on deuterides. Tuning through the onset of magnetic ordering by means of H absorption was found for the U2T2X compounds as U2Co2Sn. For U2Ni2SnD1.8, we demonstrated that the anisotropic lattice expansion leads to U moments reorientation, as a result of hybridisation-induced two-ion anisotropy,with respect to U2Ni2Sn, in which the U U coordination is poised between two regimes.JRC.E.6-Actinides researc

Magnetic Properties of UFe2+xUFe_{2+x} Prepared by Splat Cooling

A series od $UFe_{2+x}$ materials was prepared using splat cooling. The Laves phase structure can accommodate up to 0.3 Fe excess, while $T_C$ is enhanced from 172 K to approximately 240 K. Higher Fe concentration leads to the segregation of α-Fe. $\text{}^{57}Fe$ Mössbauer spectroscopy indicates higher Fe magnetic hyperfine fields on Fe nuclei occupying the U sublattice than for the regular Fe sites