Micromagnetic Simulation of Thermal Activation Volume in Perpendicular Recording Media With Dispersions of Grain Size

摘要

The process of thermal switching and thermal activation volume of perpendicular recording media with dispersions of grain size have been analyzed using micromagnetic simulation with Voronoi lattice model. It was found that in media with smaller inter-grain exchange coupling$w$, almost all grains switch thermally alone, and the average activation volume$langle V_ acrangle$does not depend on the applied DC reverse field significantly. While, in media with larger$w$, several neighboring grains switched simultaneously and$langle V_ acrangle$increased with increasing reverse field, but not so much. It was also found that$langle V_ acrangle$increased slightly with$w$until$w$reached some critical value, beyond which$langle V_ acrangle$increased remarkably with$w$.