NQR Study of Filled Skutterudite CeT4Sb12(T = Ru and Os)

Sb nuclear quadrupole resonance (NQR) experiment has been performed on filled skutterudite compounds CeOs 4 Sb 12 and CeRu 4 Sb 12 in order to investigate an electronic state from a microscopic point of view. Five NQR transitions originate from 121 Sb and 123 Sb were observed and the nuclear quadrupole frequency and asymmetry parameter were estimated. 1/ T 1 T 's shows exponential-like decrease with decreasing temperature above 100 K, indicating a presence of c – f hybridization gap for both compounds. 1/ T 1 T 's start to increase and show characteristic temperature dependence 1/ T 1 T ∝ T - n ( n =1/2 and 1) for CeOs 4 Sb 12 and CeRu 4 Sb 12 below ∼30 K, indicating a development of the spin fluctuation. The non-Fermi-liquid behavior in CeRu 4 Sb 12 is suggested to be caused by a magnetic instability.