Evaluation of inter-granular coupling in stacked perpendicular recording media

The trial for quantitative evaluation of inter-granular coupling in stacked perpendicular recording media is reported. The evaluation is realized by analyzing magnetic domain in relation with microstructure of the cap layer initial growth layer. When the thickness of cap layer is increased, the change of magnetic domain from single magnetic domain to maze magnetic domain can be observed. The critical thickness of the cap layer where the change happened was around 5.1 nm. According to this analysis, when granular layer and cap layer of stacked media are assumed to be single layer, inter-granular coupling with amount of around 2.9 erg/cm2 was obtained which agrees with the simulation result qualitatively.