Magnetic film thickness effects on the recording performance of perpendicular media

This paper reports on a systematic study of the effect of magnetic film thickness on the recording performance of perpendicular double-layered media. We found that the signal-to-noise ratio of the media decreases with increasing film thickness. This is mainly caused by the poorer head field gradient that results from the increased gap between the pole surface of the head and the top of the soft underlayer of the media. A theoretical study confirms the experimental findings.