Perpendicular recording: the promise and the problems

Perpendicular recording has long been advocated as a means of achieving the highest areal densities. In particular, in the context of the 'superparama gnetic limit', perpendicular recording with a soft underlayer promises seve ral key advantages. These advantages include a higher coercivity, thicker m edia that should permit smaller diameter grains and higher signal-to-noise ratio. Also, the sharper edge-writing will facilitate recording at very hig h track densities (lower bit aspect ratio). Recent demonstrations of the te chnology have shown densities comparable with the highest densities reporte d for longitudinal recording. This paper further examines the promise that perpendicular recording will deliver an increase in areal density two to ei ght times higher than that achievable with longitudinal recording. There ar e a number of outstanding issues but the key challenge is to create a low-n oise medium with a coercivity that is high and is much larger than the rema nent magnetization. (C) 2001 Elsevier Science B.V. All rights reserved.