A method for the numerical simulation of the thermal magnetization fluctuations in micromagnetics

Abstract

A new method for the numerical modelling of the thermal fluctuations in micromagnetic systems is presented. The approach is based on the set of stochastic Langevin equations, which are derived from the energy expression for the system studied. The correlation matrix of the corresponding random forces required to perform numerical simulations is evaluated using the fluctuation-dissipation theorem following a transformation to the normal coordinates. The method is tested for the finite 1D chain of classical magnetic moments. The temperature dependence of the average magnetization deviation Delta M/M(O) exhibits good agreement with analytical theory.