CU-63 NUCLEAR-RELAXATION IN THE SPIN-PEIERLS COMPOUND CUGEO3

We have measured the temperature dependence of the nuclear spin-lattic e relaxation rate 1/T-1 and the nuclear spin-spin relaxation rate 1/T- 2G due to indirect nuclear coupling for Cu-63 NQR in the spin-Peierls (SP) compound CuGeO3, which undergoes the SP transition at T(SP)simila r to 14 K, using a single crystal. We perform a combined analysis of 1 /T-1 and 1/T-2G on the basis of theoretical results recently obtained for the S=1/2 one-dimensional Heisenberg antiferromagnet (1DHAF) model to clarify the spin dynamics. Consequently we find that the spin dyna mics above T-SP in CuGeO3 is not described by the pure S=1/2 1DHAF mod el.