Spin Gap Behavior of<i>S</i>=1/2 Quasi-Two-Dimensional System CaV₄O₉

Abstract

Spin susceptibility and spin-lattice relaxation rate of 51 V nuclear moments of CaV 4 O 9 with tetragonal structure have been measured. They exhibit characteristics of spin gap systems. This provides the first example of quasi-two-dimensional spin systems with spin gap.