Change in valence of Ce ions induced by hydrogen absorption : CeRu2

Abstract

Ternary hydrides of superconducting cubic Laves-phases CeRu2 and LaRu2 have been prepared. The cubic structure is preserved and a considerable lattice expansion is observed. Magnetic susceptibility measurements show the disappearance of the superconducting transition for both hydrides, and in the case of CeRu 2, the appearance of a susceptibility peak at T ∼ 1.4 K. For CeRu2 hydride, the hydrogen could be removed and superconductivity reestablished. Magnetization measurements of CeRu2 hydride and comparison of its lattice parameter with that of LaRu2 hydride indicate that, with hydrogenation, the valence of Ce has changed from 4 to 3