The role of the gap in single pole heads in perpendicular recording

Summary form only given. It is commonly believed that to achieve high recording performance, the gap between the leading and trailing poles in a single pole head (SPH) has to be long with respect to the . Such an SPH is referred to as type I. An SPH in which the gap length is small air bearing surface (ABS) to soft underlayer (SUL) spacing with respect to SUL-to-ABS spacing is referred to as type II. In this work, the recording characteristics of type II and type I SPHs are compared. For clarity, SPH and RH imply the presence and the absence of a SUL, respectively. It should be stressed that recording on a medium with a RH is fundamentally different from recording with a SPH. In recording with a SPH, the writing is done by the trailing edge of the trailing pole. This is in contrast to recording with a RH, in which the writing is done by the trailing edge of the gap. A conventional RH used to write onto a medium with a SUL acts as a type II SPH.