Switching speed limitations in perpendicular magnetic recording media

A method to study switching speed limitations in high-frequency magnetic recording is presented. The characteristic parameter is the minimum irreversible switching time that is evaluated by numerical simulation of the writing of a dibit of two transitions using Landau–Lifshitz dynamics. The dibit is written on a perpendicular polycrystalline thin film medium using a single-pole head with a soft underlayer. We study the physical factors that determine the ultimate data rate and consider the problem of optimization of switching speed by changing the relative head-medium velocity, the magnetocrystalline anisotropy, the rise time of the head field, the head-medium separation, the exchange intergranular coupling, and the dispersion in the direction and magnitude of the local anisotropy.