Effect of angle dependent attempt frequency on Arrhenius-Neel thermal decay in thin film media

The angle dependence of the attempt frequency f₀ has been determined by assuming isotropic thermal excitation in the anisotropic free energy around the easy axis of a single-domain particle. The relationship between the logarithmic time and the time-dependent remanence coercivity H_cr was estimated. The acquired equation agrees sell with the numerical calculation of the Langevin equation. The conventional formula do not give the correct relationship between H_cr and K_β(=Kv/kT) because the exponent of K_β depends on K_β. The estimated K_β from Sharrock´s formula is 15% larger at K_β of 100 and 5% smaller at K _β of 50. Bertram´s formula is effective at K_β of 100 but brings 7% smaller estimation at K_β of 50