A path for conventional perpendicular recording to reach 1 Tb/in.2 and beyond

In this paper, we report micromagnetic analysis of a scheme for increasing area density capability in conventional perpendicular magnetic recording. By replacing a significant portion of the Ru intermediate layer in present film media with appropriate soft magnetic material, recording head field gradient can be effectively enhanced. A combined finite element method (FEM) and micromagnetic modeling study is conducted for the quantitative understanding of the area density gain along with recording geometry optimization. FEM calculation shows that by reducing air bearing surface to soft underlayer separation from 50 to 30 nm and the write gap from 35 to 20 nm, the on-track field gradient increases from 560 to 820 Oe/nm. The corresponding recording simulation on the same single layer medium shows almost 2 dB medium signal-to-noise ratio gain. The study also shows that the vertically segmented three-layer media used in current disk products can effectively further enhance the head field gradient, provided adequate vertical exchange coupling between the segments. (C) 2011 American Institute of Physics. [doi:10.1063/1.3556774]