Computer simulation of high-speed magnetization switching in hard-disk media

Magnetization-switching behavior was investigated in high-data-rate hard-disk media through micro-magnetic simulation to clarify the distinction between the gyromagnetics dominated scheme and the thermodynamics dominated scheme in the dynamics of the switching. It was found that the pulse-shape dependence of remanence coercivity H_cr and the anisotropy field H_k dependence of the switching-speed are caused by the gyromagnetic effect. The thermodynamic effect plays a main role in the time-dependent H_cr when the pulse width is over 1 ns. On the other hand H_cr in the thermodynamic region decreases linearly with respect to the logarithmic pulse width. The demagnetizing field from the write bubble causes H_cr to increase with the reverse DC erase (RDC) method in 10 or fewer “reptations”