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.

Autoresonant control of the magnetization switching in single-domain nanoparticles

“…Carlo simulations [55][56][57]. One can write the linearized LLG equation for the normalized moment m in the form:…”

Classical spin model of the relaxation dynamics of rare-earth doped permalloy

“…16 Using this method, the nonequilibrium dynamics at a finite temperature can be described using the Landau-Lifshitz-Gilbert Langevin equation. 17 To quantify the demagnetization time from the simulations, the integral relaxation time 18 (IRT) is used. The model incorporates two thermal reservoirs; representing the conduction electrons and the lattice, the thermodynamics of which are represented by the two-temperature model.…”

Thermal effects on transverse domain wall dynamics in magnetic nanowires

“…Consequently, thermal effects should be taken into account in the design and should first be understood. In micromagnetic simulations, thermal fluctuations are either included by a jump-noise process 6,7 or a stochastic field 8 as determined by Brown. 9 Using this approach, the influence of thermal fluctuations at high driving forces has been investigated.…”