Evidence for Magnetic Ordering Associated with Metal-Insulator Transition in SmRu4P12 Studied by Muon Spin Relaxation

Muon spin relaxation measurements on the filled skutterudite compound SmRu4P12 have been carried out in zero- and longitudinal-fields. Temperature dependence of both initial asymmetry and muon-spin depolarization rate show the appearance of a magnetically ordered state below the metal-insulator transition temperature TMI. The present study indicates that the ordering below TMI is not a non-magnetic antiferro-quadrupolar ordering but a magnetic one, which supports a scenario that a magnetic octupolar ordering occurs below TMI in SmRu4P12.