Finite temperature micromagnetics and magnetic measurements of submicron patterned permalloy thin films

Micromagnetic simulation using the deterministic Landau–Lifshitz–Gilbert (LLG) equation is inadequate for predicting the coercivity of submicron patterned thin films. The discrepancy results because the deterministic LLG equation only provides a zero-temperature description of the magnetization processes of a ferromagnetic material. In order to properly simulate the coercivity, the stochastic LLG equation, which includes thermal effects through a fluctuating magnetic field, must be used. Direct comparison of measurements of the coercivity of arrays of submicron patterned permalloy thin films with simulation has been used to show that the second-order Heun scheme is adequate for this purpose. In addition, the simulated temperature dependence of the magnetization of the patterned bits tracks the measured dependence. © 2003 American Institute of Physics.