Low-temperature defect study of α-LuH(D)xsolid solutions

Abstract

Abstract Solid solutions of hydrogen or deuterium in lutetium exhibit, when quenched across the well-known 170K anomaly and/or irradiated with electrons at low temperatures, a residual-resistivity increase, Δρq and Δρirr. The former is a linear function of x for LuH(D)x with 0≤x≤0·19. Δρirr manifests a strong isotope effect and varies faster than linearly with x for LuHx, it decreases with increasing electron energy E in the measured interval 0·4≤E≤0·8 MeV (subthreshold with regard to the Lu atoms). The energy dependence of Δρirr has been fitted with electron-hydrogen displacement cross-sections, taking into account the secondary electrons produced by the primaries in the samples. The H(D)-displacement threshold has been assimilated to a binding energy, E b in a short-range ordered configuration; it has been determined from a comparison of the H-resistivities, ρH(T), above and below the anomaly: E b(H) = 63±2 meV and E b(D) = 73±5 meV. The fit of the calculated cross-sections to the experimental data yiel...