Kinetic Monte Carlo simulations of a model for heat-assisted magnetization reversal in ultrathin films

Abstract

To develop practically useful systems for ultra-high-density information recording with densities above terabits/cm 2 , it is necessary to simultaneously achieve high thermal stability at room temperature and high recording rates. One method that has been proposed to reach this goal is heat-assisted magnetization reversal (HAMR). In this method, the magnetic orientation is assigned to a high-coercivity material by temporarily reducing the coercivity during the writing process through localized heating. Here we present kinetic Monte Carlo simulations of a model of HAMR for ultrathin films, in which the temperature in the central part of the film is momentarily increased above the critical temperature, for example by a laser pulse. We observe that the speed-up achieved by this method, relative to the switching time at a constant, subcritical temperature, is optimal for an intermediate strength of the writing field. This effect is explained using the theory of nucleation-induced magnetization switching in finite systems. Our results should be particularly relevant to recording media with strong perpendicular anisotropy, such as ultrathin Co/Pt or Co/Pd multilayers.

Monte Carlo simulations of intragrain spin effects in a quasi-2D Heisenberg model with uniaxial anisotropy

“…A key measure of the relative importance of intragrain degrees of freedom in this study was the dependence of the system Curie temperature on J and its deviation from the linear dependence expected of the homogeneous 2D Ising model (J = J ′ ). The results of kinetic MC simulations of an Ising model of the homogeneous 2D system to represent recording media for HAMR applications have also been reported [7].…”

Magnetisation reversal in Ising ferromagnet by thermal and field gradients

“…Here the competing effects of reversal time and the rate of spreading have been discussed. The effects of the rate of changing the temperature on the reversal time was investigated [10] , recently. The magnetisation switching in classical Heisenberg model for small ferromagnetic particles was studied extensively [11] .…”

Parallelization and implementation of multi-spin Monte Carlo simulation of 2D square Ising model using MPI and C++

“…Monte Carlo methods or statistical simulation methods are widely used in different fields of science such as physics, chemistry, biology, computational finance and even new fields like econophysics [4,5,6,7,8,9]. The simulation can proceed by sampling from the Probability Density Function (PDF) and generating random numbers uniformly.…”