Dieter Weller, IBM Almaden Research Center, 650 Harry Road, San Jose, CA 95120

Areal density progress in magnetic recording is largely determined by the ability to fabricate low noise granular thin film media with sufficient stability against thermal agitation to warrant long term data storage. A key requirement is a medium microstructure with small, magnetically isolated grains to establish optimal macro- and micro-magnetic properties. A lower bound for the minimal average grain diameter, compatible with thermal stability, is imposed by the write field capability of the recording head. It is 10-12 nm assuming maximal writeable coercivities of about 5000 Oe. These are already achieved in today’s state-of-the-art CoCr-based thin film alloy media, leaving little room for further improvements and density gains based on continued grain size reduction. A three fold reduction in grain diameter, however, translating into a ten fold increase in areal density is theoretically possible, if write field constraints can be overcome, allowing utilization of magnetically harder alloys. In this talk, we emphasize materials and fabrication aspects behind media for extremely high-density longitudinal magnetic recording. Special attention is paid to thermal stability and write coercivity constraints. Various alternative media designs for extremely high density recording beyond 40-100 Gbits/in2 will be reviewed.