The Effect of Hydrogen Absorption on the Structural, Electronic and Magnetic Properties of the C15 Friauf-Laves Phase Compounds CeFe2, CeRu2 and LaRu2 : an X-Ray Absorption Spectroscopy (XAS) Study

We present an x-ray absorption spectroscopy (XAS) investigation of the structural changes occurred upon hydriding in the Friauf-laves phase compounds CeFe2, CeRu2 and LaRu2 compounds. The analysis of the extended x-ray absorption spectroscopy (EXAFS) spectra at the L-edges of the rare-earth and at the Fe K-edge indicates that the hydrogenation process leads to the suppression of the long-range crystalline order in all the hydride derivatives investigated, as well as the different influence of H2 in both the rare earth and transition metal sublattices. The correlation between the structural and magnetic changes introduced by the hydrogen in the host matrix is discussed in terms of the modification of the electronic properties, i.e., intermediate-valence state of Ce, and of the hybridization between the transition metal and the rare-earth.