Numerical study of spin relaxation by thermal fluctuation: Effect of shapeanisotropy

Effects of the shape anisotropy on the thermally activated spin relaxation have been investigated using the stochastic Landau-Lifshitz-Gilbert equatio n. The relaxation times of a noninteracting particle and a thin film were c ompared with each other. In a noninteracting particle, the relaxation time largely increased with the shape anisotropy when the damping constant was s maller than a certain critical value. In this study, the critical damping c onstant was 0.02. However, the effect of the shape anisotropy on the energy barrier was negligible in a thin film. All of these results can be explain ed from the effect of magnetostatic interaction that is enhanced by precess ion motion at low damping constant. (C) 2001 American Institute of Physics.