Reversal time of the magnetization of single-domain ferromagnetic particles with cubic anisotropy in the presence of a uniform magnetic field

The reversal time of the magnetization of a single-domain ferromagnetic particle with a cubic anisotropy in the presence of a uniform magnetic field is evaluated using the Kramers escape rate theory for intermediate-to-high damping as extended by Brown [W. F. Brown, Jr., IEEE Trans. Magn. 15, 1196 (1979)] to the analogous magnetic spin problem. It is shown that this formula is in complete agreement with the relaxation time calculated numerically from the solution of the stochastic Landau-Lifshitz-Gilbert equation describing the dynamics of the magnetization of the particles. It is also shown that knowledge of the reversal time τ allows one to predict accurately the spectrum of the longitudinal magnetic susceptibility in the low-frequency range.