The current status and future of granular media

The current status of CoPtCr-SiO2 granular media is briefly reviewed, and challenges relative to media technology exceeding 1 Tb/in2 are discussed. It is effective to enhance grain isolation using oxide materials that easily precipitate at the grain boundary, and this technique is adopted in commercially available perpendicular recording media. Although some difficulties such as reduction of the grain size retaining the switching field remain, 1 Tb/in2 could be achieved by using granular exchange-coupled composite-type media or related technologies. Discrete track media could be used for more than 1 Tb/in2 recording. It could also take several years to further develop nano-processing technology and establish a cost-effective infrastructure. BPM offers great potential in achieving high recording density, although some necessary technologies are still too primitive to consider commercial production.