Switching time of single magnetic particle and maximum recording frequency of perpendicular magnetic recording

We investigated the switching time of a magnetic particle-which may impose limits on magnetic recording frequency-by computer simulation. We found that the difference in switching time between low and high temperatures decreases with increasing the angle ξ between the applied field and the easy direction, and scarcely changes with temperature if the angle is larger than a few degrees. This can be explained by considering the energy contour and locus of magnetization in switching. The switching times derived by using divided models, in which the particle is divided into 2×2×2 or 4×4×4 cells, are smaller than those derived by using an undivided model. But the difference between the switching times derived with the divided and undivided models is less than 1% if the angle ξ is larger than 1°. We derived equations to express the switching times of the particle for the divided models at ξ=0, and we used the equations to estimate the maximum recording frequency in perpendicular recording.