U Mssbauer study on the 5f-quadrupoles in uranium-based intermetallics

ウラン金属間化合物における5f四極子のUメスバウアー分光による研究

筒井 智嗣*; 中田 正美  ; 那須 三郎*; 本間 徹生*; 常盤 欣文; 青木 大*; Wisniewski, P.*; 芳賀 芳範   ; 大貫 惇睦

Tsutsui, Satoshi*; Nakada, Masami; Nasu, Saburo*; Homma, Tetsuo*; Tokiwa, Yoshifumi; Aoki, Dai*; Wisniewski, P.*; Haga, Yoshinori; Onuki, Yoshichika

多くのウラン化合物についてメスバウア分光測定を行い、電子状態を反映した四極子分裂を観測した。

We have determined the distribution of the 5f-quadrupoles and detected the 5f-quadrupole order in the uranium intermetallics, uranium dipnictides and UPd, with Mo"ssbauer spectroscopy. We have declared that the distribution of the 5f-quadrupoles depends on the magnetic sequence in uranium dipnictides. The distribution of the 5f-quadrupole is spherical in UBi, while those are oblate within c-plane in UP, UAs and USb. We have observed the sudden drop of the recoil-free fraction above the transition temperature of the quadrupole order in UPd. The present result suggests the change of the phonon states due to the quadrupole order in this compound.