Minimum particle volume of tilted and composite media considering magneto-static interactions

The areal density limit of magnetic recording is determined by the minimum magnetic grain size of the recording medium. Thermal stability sets this minimum, which is limited by the maximum head field. To extend this density limit, tilted media (TPR), which inclines the anisotropy angle, and composite media, which comprises a hard and soft magnetic sub-grain with weak exchange coupling have been proposed. In this study, we compare the advantage of these media theoretically to conventional perpendicular recording (CPR), especially focusing on the role of the magneto-static interaction. Here the magneto-static interaction includes both the thin film demagnetizing field and the coupling between the two sub-grains of the composite media.