LAUSR

In order to enhance the performance of advanced granular recording media and understand the physics behind the mechanism of the reversal process, an atomistic spin-dynamics simulation is used to investigate theoretically the magnetic properties and the magnetization-reversal behavior for a composite media design. This model allows us to investigate the effect of the magnetostatic interaction and inter- and intralayer exchange coupling for a realistic system. The composite granular medium investigated consists of hard and soft composite layers in which the grains are well segregated with a continuous capping layer deposited to provide uniform exchange coupling. We present a detailed calculation aimed to reveal the reversal mechanism. In particular, the angular dependence of the critical field is investigated to understand the switching process. The calculations show a complex reversal mechanism driven by the magnetostatic interaction. It is also demonstrated, at high sweep rates consistent with the recording process, that thermal effects lead to a significant and irreducible contribution to the switching field distribution.