Structural transition in rare-earth hydride under pressure

Aoki, Katsutoshi; Machida, Akihiko; Omura, Ayako*; Watanuki, Tetsu; Takemura, Kenichi*

Structural investigation on metal hydrides provides an insight into the interactions between hydrogen atoms occupying the interstitial spaces of a metal lattice. The hydrogen atoms are often negatively ionized due to the charge transfer from the host metal lattice and the electrostatic forces play a dominant role in structural stabilization or transition. Synchrotron X-ray diffraction measurements were made for di-hydrides and tri-hydrides of rare-earth metals (Sc, Y, La) at pressures up to 50 GPa and at ambient pressure at SPring-8.