Charge fluctuation in Ce-based filled-skutterudite

Abstract

We carried out 121,123Sb nuclear quadrupole resonance (NQR) measurement on CeOs4Sb12 to investigate an anomaly observed in ReOs4Sb12. The full width of half maximum of the NQR spectrum shows a step-like increase at 115 K with decreasing temperature (T). The nuclear spin-spin relaxation rate 1/T2 also shows a divergence at the same T. These results are considered to be caused by a distribution of the electric field gradient (EFG) and its fluctuation, which might arise from a small deformation of the cage which consists of twelve Sb. It is considered that the anomaly observed in ReOs4Sb12 at T ∼ 120 K is originated from an unique crystal structure of the filled skutterudite. © 2009 IOP Publishing Ltd.