Relationship between head design, pole-tip magnetization, head field, and media magnetization in longitudinal recording

We investigated the relationship between head design, pole-tip magnetization, head field, and media magnetization in longitudinal recording. At first we estimate the effective switching field of current mobile media with isotropic anisotropy, and introduce longitudinal corresponding field for the head field assessment. The smaller perpendicular component or large perpendicular field gradient of the head field at the upper pole improves the transition quality, but the small perpendicular field degrades the overwrite performance. So the ideal head field is large longitudinal and perpendicular field for good overwrite and fast attenuation with the large perpendicular field gradient for the transition quality. Some head designs make it possible to control the ratio of the perpendicular component to the longitudinal head field, by changing the pole-tip magnetization direction. As a project to control it, we discuss the effect of the bottom and upper poles configuration on the transition, overwrite, and adjacent track erasure in longitudinal recording.