A Mechanism for Enhancing the Reproduced Voltage on the Ring-Type-Head/Electroless-Deposited Perpendicular Double-Layered Media System.

A mechanism was investigated for enhancing the reproduced voltage of the ring-type-head/electroless-deposited perpendicular double-layered medium system. The enhancement mechanism was considered to combine the fo1lowing two effects: the “phase synchronization (PS) effect”, due to a semihard magnetic underlayer, and the “double-layered (DL) effect”, due to a softmagnetic underlayer. By proper AC erasing of the reproduced signal due to the underlayer (underlayer coercivity (Hc(u)=50Oe) on a CoNiReP/CoB double-layered medium, the PS effect was confirmed to appear until the recording density of the region was less than 90 kFRPI. The enhancement of the reproduced voltage in a region where the density was higher than 90 kFRPI was still observed after such a proper AC erasing process, and it originated solely from the DL effect.