Longitudinal Recording at 10 to 20 Gbit/[inch.sup.2] and Beyond

It is common understanding that superparamagnetic effects will eventually limit the maximum recording density of magnetic hard disk recording. This contribution reviews the theoretical concepts of noise in magnetic recording as well as the concepts of thermally activated magnetization reversal. The theoretical results are contrasted with experimental data. The findings clearly indicate that at some point, signal-to-noise ratio has to be compromised with the thermal stability of the written information. Index Terms -- Magnetic recording, signal-to-noise ratio, superparamagnetic effects, thermal activation, thin film media.