Abstract
We have carried out 121,123 Sb nuclear quadrupole resonance (NQR) measurements on Re Ru 4 Sb 12 ( Re = La, Ce and Pr) to investigate an anomalous behavior of the nuclear spin–echo relaxation rate 1/ T 2 observed in Re Os 4 Sb 12 . The full width at half maximum of the NQR spectrum shows a step-like increase below 130 K with decreasing temperature. Temperature dependence of 1/ T 2 also shows a divergence at ∼115 K whereas the nuclear spin–lattice relaxation rate 1/ T 1 does not show any anomaly. These results are caused by a distribution of the electric field gradient (EFG) and its fluctuations, which might arise from a rattling motion of the rare earth ion centered in the cage which consists of twelve Sb and/or a small deformation of the cage. The EFG fluctuations observed in Re Os 4 Sb 12 and Re Ru 4 Sb 12 at T ∼120 K originates from an unique crystal structure of the filled skutterudite with oversized Sb-cage.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
