SNR improvement of granular perpendicular recording media

In this paper, we address important issues on the performance improvement of perpendicular magnetic recording (PMR) media, such as noise reduction by adjusting the soft magnetic underlayer (SUL) properties and recording layer and intermediate layer modifications for optimum signal-to-noise (SNR) performance. The permeability of the SUL plays a significant role in writability and SNR. Proper pinning of the SUL should be considered for reducing spike noise. A systematic comparison of alloy and oxide granular media shows that optimized oxide media can provide both better SNR and good thermal stability and is promising for high-density recording.