Change in V-51 relaxation rates due to CDW in CuV2S4

The temperature variations of the Cu-63, Cu-65 and V-51 NMR spectra and V-51 spin-lattice relaxation rate 1/T-1 have been measured in a thiospinel CuV2S4. Drastic changes in the spectra and relaxation rates were observed at the charge density wave (CDW) transition temperature. With decreasing temperature T, 1/T-1 decreases exponentially due to the CDW transition (75 K < T < 90 K). The energy gap made by the CDW formation at 90 K is estimated to be 0.052 eV from an Arrhenius plot of 1/T-1.