Dynamics in the S = 1 one-dimensional antiferromagnet AgVP₂S₆ via 31P and 51V NMR

The nuclear spin-lattice relaxation rate (1/T1) has been measured at 31P and 51V nuclei in the one-dimensional spin-1 antiferromagnet AgVP2S6 single crystal. In addition to an activated temperature dependence, 1/T1 at P sites shows 1/√H magnetic field dependence due to spin diffusion above a certain cutoff field at high temperatures. While the diffusion constant shows a modest temperature dependence, the cutoff field increases rapidly on cooling. The spin-diffusion model is incompatible with the data at low temperatures, suggesting a crossover at T∼100 K. © 1996 The American Physical Society.