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/sub cr/ and the anisotropy field H/sub k/ dependence of the switching-speed are caused by the gyromagnetic effect. The thermodynamic effect plays a main role in the time-dependent H/sub cr/ when the pulse width is over 1 ns. On the other hand H/sub cr/ in the thermodynamic region decreases linearly with respect to the logarithmic pulse width. The demagnetizing field from the write bubble causes H/sub cr/ to increase with the reverse DC erase (RDC) method in 10 or fewer "reptations".