The effect of temperature is rarely taken into account in micromagnetic calculations. However, thermal perturbations are known to play an important role in magnetization reversal processes. In this article, a micromagnetic model that includes thermal perturbations is presented. A stochastic zero-mean Gaussian field is introduced in the Landau–Lifschitz–Gilbert equation and the corresponding Langevin equation is solved numerically. The model is used to study the effect of temperature on the coercivity of domain walls due to exchange and anisotropy wells as well as nonmagnetic inclusions. It is shown that, for exchange and anisotropy interactions, thermal perturbations can lower the critical field for which the wall breaks free from the inclusion. However, when magnetostatic fields are taken into account, thermal perturbations are found to inhibit the unpinning process. This phenomenon seems to be related to the long-range nature of dipolar interactions.

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© 1999 American Institute of Physics.
1999
American Institute of Physics
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