NMR Studies of Half-Heusler Type Compounds YbPtSb and LuPtSb

Abstract

The 121/123 Sb and 195 Pt nuclear magnetic resonance (NMR) results are presented for the half-Heusler compound YbPtSb. The characteristics of localized 4 f spins were observed in the Cure–Weiss type behavior of Knight shifts. The spin–lattice relaxation rate (1/ T 1 ) gradually increases with decreasing temperature and shows a maximum at around 20 K. An approximate analysis of the 4 f spins correlation rate 1/τ f was performed using the measured values of 1/ T 1 and bulk susceptibility. We observed a √T dependence of 1/τ f between 10 and 220 K, which is indicative of an existence of isolated local moment fluctuations. The spin–echo decay rate exhibits a distinct peak at 10 K. We suppose this peak is associated with the magnetic fluctuation originating from 4 f electrons. The crystalline defects in the half-Heusler compounds are also discussed together with the NMR results in LuPtSb.