Na-23 NMR study of spin-peierls transition in NaV2O5

Na-23 NMR spectrum measurements in a spin-Peierls system, NaV2O5, are presented. Below the spin-Peierls transition temperature (T-sp), two distinct sites of Na appear, confirming the structural phase transition at T-sp. The orbital susceptibility was evaluated using the temperature dependence of the Na-23 NMR shift; it is suggested that the orbital susceptibility changes near T-sp. The temperature dependence of the spin susceptibility obeys an activation law below similar to 20 K with a gap of 98 K.