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 tau allows one to predict accurately the spectrum of the longitudinal magnetic susceptibility in the low-frequency range. (C) 2007 American Institute of Physics.