Dependence of switching time on temperature, applied field, and material parameters

The switching time of a single-domain particle with uniaxial anisotropy subjected to an applied field along the easy axis is studied by solving Brown´s Fokker-Planck equation numerically. The equation is modified in order to be integrated by a finite-difference method. The validity of this method is verified by comparing the frequency prefactors in the exponential decay calculated by this method with the values from Brown´s formula for the prefactor. Switching times for several values of the applied field and the temperature are calculated. Curves of the inverse of the switching time are fitted to a simple expression by using a least-squares method. The expression consists of two terms: a linear function of the applied field and a function proportional to the square root of the temperature. The dependence of the switching time on the magnetization, the volume of the particle, the anisotropy field, the Gilbert´s damping constant, and the gyromagnetic constant is also presented.