Magnetic properties, magnetic cluster size, and read-write performance of CoPtCr-SiO/sub 2/ perpendicular recording media

The characteristics of CoPtCr-SiO/sub 2/ perpendicular media were investigated, especially focusing on the dependence of magnetic properties and read-write performance on magnetic cluster size. H/sub c/ increases with reducing magnetic cluster size. As magnetic cluster size decreases, media noise and signal-to-noise ratio are improved and magnetic write width becomes narrower, indicating that reducing the magnetic cluster size is an effective means to increase both bit and track densities. However, diminution of magnetic cluster size degrades thermal stability. Lowering the magnetic cluster size threshold, above which a medium is thermally stable, is necessary in order to obtain a low noise and thermally stable medium.