Physics of perpendicular recording with a patterned soft underlayer.

In this paper, it is argued that perpendicular recording in the most popular current form--with the use of a continuous soft underlayer (SUL)--may not be the most optimal way to maximize the achievable areal density. As a possible solution, patterning of SUL is discussed. The purpose of patterning of a SUL is to effectively move the image head closer to the recording media, as compared to the real recording head, and thus increase the net recording field and the field gradient across the thickness of the media. Various patterning configurations and combinations with recording layers are comparatively studied. It is illustrated that with a patterned SUL, the recording and sensitivity fields, responsible for writing and reading information, respectively, could be not only increased by several factors but also localized across the entire thickness of the recording media.