Physics of perpendicular recording: effects of magnetic charge distribution

Summary form only given. The nature of the stray and demagnetizing field in perpendicular media is drastically different from what is observed in conventional longitudinal recording. In contrast to longitudinal recording, in perpendicular recording the magnetic "charges," which are the effective sources of the demagnetization and stray fields, are concentrated not at the transitions but at the top and effective bottom surfaces of the recording layer (RL). Based on analytical calculations and 3D-boundary element modeling a detailed analysis of the stray and demagnetization fields for perpendicular RL as functions of the areal bit density, the bit-aspect-ratio (BAR), linear and track densities, and the RL thickness is presented. The observed dependencies are contrasted to dependencies observed in longitudinal recording.