Direct calculation of the attempt frequency of magnetic structures using the finite element method

A numerical implementation of the transition state theory is presented which can be used to calculate the attempt frequency f0 of arbitrary shaped magnetic nanostructures. The micromagnetic equations are discretized using the finite element method. The climbing image nudged elastic band method is used to calculate the saddle point configuration, which is required for the calculation of f0. Excellent agreement of the implemented numerical model and analytical solutions is obtained for single domain particles. The developed method is applied to compare f0 for single phase and graded media grains of advanced recording media. f0 is predicted to be comparable if the maximum anisotropy is the same in these two media types.