PHASE-TRANSITION AND SPIN DYNAMICS IN LIVO2

The phase transition and the spin dynamics in a triangular lattice compound LiVO2 have been studied through magnetic susceptibility and NMR measurements. It has been found that the quadrupole effect and the anisotropy of the Knight shift of the V-51 nuclei are appreciably induced due to the distortion of the local symmetry at the V ions below the nonmagnetic-magnetic transition temperatures which are about 500 K on heating and 440 K on cooling. The electronic state and the spin dynamics of V ions above the transition have been explained by the localized spin model with the spin number S = 1. It has also been suggested that the dynamics from the transition to about 140 K may be described by the thermally excited spin whose ground state is possibly spin-singlet due to the trimerization of V3+ ions.