Structural properties of yttrium trihydride under high pressure

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

Yttrium metal hydrides, which enable to contain three hydrogen atoms per one yttrium atom, are regarded as high density hydrides. In yttrium hydrides, the di-hydride shows the metallic behavior while the tri-hydride insulating. In these hydrides, it is considered that the hydrogen-hydrogen interactions can not be negligible for structural and physical properties under high pressure. Then, we have investigated the structural properties of yttrium hydrides by synchrotron radiation X-ray diffraction measurements under high pressure. We have found the characteristic structural features for yttrium hydrides under high pressure. In my talk, the high-pressure structural properties for the intermediate state between hexagonal and cubic phase in yttrium tri-hydrides will be discussed.