^{<b> 23</b>}Na NMR Study of Spin-Peierls Transition in NaV_{<b> 2</b>}O_{<b> 5</b>}

Abstract

23 Na NMR spectrum measurements in a spin-Peierls system, NaV 2 O 5 , 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 23 Na 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 ∼20 K with a gap of 98 K.