Thermal demagnetization analysis of CoPt magnetic recording medium by magneto-optical recording test

The thermal demagnetization process of granular CoPt perpendicular magnetic recording medium was studied by a magneto-optical recording test. Signals from recorded magnetic domains decreased by continuous laser irradiation at relatively high power. This phenomenon was caused by an acceleration of the thermal decay of written domains, which might become a crucial issue for the design of a thermally-assisted magnetic recording system. A new simple model was proposed for the analysis of the thermal degradation of this experiment. This model was in good agreement with the experimental results. According to this model, an enhancement of areal density by employing the thermally-assisted recording was roughly estimated. For the case of the examined samples, the enhancement of the areal density was about two. Possible ways to avoid the acceleration were also discussed using this model.