Stochastic form of the Landau-Lifshitz-Bloch equation

Abstract

The Landau-Lifshitz-Bloch equation is a formulation of dynamic micromagnetics valid at all temperatures, treating both the transverse and longitudinal relaxation components important for high-temperature applications. In this paper we discuss two stochastic forms of the Landau-Lifshitz-Bloch equation. Both of them are consistent with the fluctuation-dissipation theorem. We derive the corresponding Fokker-Planck equations and show that only the stochastic form of the Landau-Lifshitz-Bloch equation proposed in the present paper is consistent with the Boltzmann distribution at high temperatures. The previously used form does not satisfy this requirement in the vicinity of the Curie temperature. We discuss the stochastic properties of both equations and present numerical simulations for distribution functions and the average magnetization value as a function of temperature.