Micromagnetic Studies of Time-Dependent Coercivity

Abstract

This paper has studied the time-dependent coercivity in both the constant-field model and changing-field model, based on a new micromagnetic method at finite temperature using the hybrid Monte Carlo (HMC) algorithm. By comparing the simulated time-dependent coercivity with Sharrock’s law, the scaling relationship between the fictitious simulation time $\tau $ in the Hamilton equations in the HMC micromagnetics and the real time t is derived, and the simulation time in a trajectory ( $\tau = 10^{-3}$ ) is found to be close to 1 ns in the real-time scale. Furthermore, we have studied the effects of the magnetic anisotropy types on the parameter $\beta $ in Sharrock’s law, and it is found that the cubic anisotropy model exhibits a larger $\beta $ value than the uniaxial anisotropy model. Our simulation results agree well with the experiments and the results from other simulation methods under certain circumstances.