Media for 10 Gb/in.² hard disk storage: Issues and status (invited)

Future 10 Gb/in.² recording densities represent submicron trackwidths and sub‐100 nm bit lengths. This requires extremely small magnetic switching units and very high coercivities of the media to satisfy the signal‐to‐noise ratio requirements. At the same time the question of magnetic thermal stability and the lack of transducers capable of performing at these densities makes it difficult to evaluate media. An uncoupled, highly uniform magnetic grain size of about 10 nm is a compromise toward maintaining an adequately low media noise and yet maintaining magnetic stability. Here we discuss current media construction, the detrimental role of substrate roughness, the role of new media structures and alloys on microstructure and magnetic properties as well as techniques for evaluating media performance prior to the availability of the required playback heads.