SPIN DYNAMICS ALONG THE CHAIN DIRECTION IN AN S=3/2, QUASI-ONE-DIMENSIONAL HEISENBERG-ANTIFERROMAGNET CSVCL3

Inelastic neutron scattering experiments investigating the spin dynamics along the chain direction of an S = 3/2 quasi-one-dimensional Heisenberg antiferromagnet CsVCl3 were performed up to the zone boundary energy. We observed the quantum renormalization in the exchange constant and found that the scattering function cannot be described by either the classical delta-function or the quantum Heisenberg model for S = 1/2. The spin excitations have apparent linewidths and they are compared with the theory of the classical isotropic Heisenberg system at finite temperatures.