Anharmonic Pr guest modes in Pr(OsRu)Sb investigated by inelastic X-ray scattering

非弾性X散乱によるPr(OsRu)Sb中のPrゲストイオンの非調和振動

筒井 智嗣; 金子 耕士   ; 宮崎 亮一*; 東中 隆二*; 青木 勇二*; 小林 理気*; 脇本 秀一  ; Baron, A. Q. R.*; 菅原 仁*; 佐藤 英行*

Tsutsui, Satoshi; Kaneko, Koji; Miyazaki, Ryoichi*; Higashinaka, Ryuji*; Aoki, Yuji*; Kobayashi, Riki*; Wakimoto, Shuichi; Baron, A. Q. R.*; Sugawara, Hitoshi*; Sato, Hideyuki*

We have investigated the Ru/Os concentration dependence of the Pr guest mode in Pr(OsRu)Sb and its variation with temperature. The Pr guest mode at 3.2 meV in PrOsSb at the N point linearly shifts to a higher energy with the substitution of Ru into the Os site. The energy of the Pr guest mode decreases with decreasing temperature for all compositions, indicating the presence of an anharmonic potential at the Pr site. The slope of the temperature dependence of the guest mode energy is steeper for pure PrOsSb than for the other Pr(OsRu)Sb compounds we measured. The present results imply the importance of the transition metal in determining anharmonicity in Pr(OsRu)Sb.