Nuclear spin relaxation in two-dimensional Heisenberg antiferromagnet S=1/2 with skyrmions

Abstract

The nuclear spin relaxation rate 1/T1 is calculated for a two-dimensional quantum Heisenberg antiferromagnet S=1/2 with thermally excited skyrmions at temperatures T≤J , where J is the nearest-neighbor exchange constant. It is found that 1/T1 first exponentially decreases with increasing temperature, passes a minimum at Tmin = 0.67J and then linearly increases before approaching its high-temperature limit. A comparison with calculations for a nonlinear sigma-model without skyrmions and experimental results is given. © 1998 Elsevier Science Ltd. All rights reserved.