Absence of pure quadrupole ordering in SmSn; Dipole-dipole and quadrupole-quadrupole interactions in Sm-based compounds

SmSnにおける純四極子秩序の欠如; サマリウム化合物における双極子間及び四極子間相互作用

伊藤 孝   ; 髭本 亘  ; 二宮 和彦; 鈴木 博之*

Ito, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko; Suzuki, Hiroyuki*

The intermetallic cubic compound SmSn is currently the only candidate for pure quadrupole ordering among existing Sm-based compounds. In this paper, we report on magnetic susceptibility and muon spin relaxation measurements on SmSn and demonstrate that a spontaneous local magnetic field appears in the ordered state, which undoubtedly rules out the pure quadrupole ordering. Dipole-dipole and quadrupole-quadrupole interactions in trivalent lanthanide systems are discussed on the basis of a de Gennes theory, indicating that the former tends to dominate in Sm intermetallics. This also provides a general guideline for future searches of quadrupole-related phenomena in trivalent lanthanide systems.