V-51-Nmr Study Of The Misfit Layer Compounds La1.17-Xsrxvs3.17

Electronic properties of La1.17-xSrxVS3.17, which undergoes a clear phase transition at around x similar to 0.17 (Or at the V-valency of +3) with decreasing temperature T to a nonmagnetic ground state, have been investigated by V-51-NMR as a function of the Sr-concentration x. The relaxation rate divided by T, 1/T1T seems to be almost T-independent for all samples studied here (0.0 less than or equal to x less than or equal to 0.35) above the phase transition temperature and becomes maximum at around x = 0.17. Below the transition, 1/T1T exhibits activation-type behavior except the very low temperature region where the T-dependence is much weaker. The activation energy decreases rapidly with increasing x: in the region of the V-valency larger than +3. The 1/T1T values of the samples with x: around 0.17 become nearly equal to zero at low temperatures, indicating that their spin susceptibilities vanish almost completely. It suggests that the transition to the nonmagnetic ground state is driven by a singlet formation with rather local nature. A plausible model of the transition is proposed to explain the present results and those of other kinds studies reported previously.