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 a recording system combining a ring head with a electroless-deposited perpendicular double-layered medium. The mechanism of enhancement is thought to consist of the following two effects: the "phase synchronization" (PS) effect, due to a semi-hard magnetic underlayer, and the "double-layering" (DL) effect, due to the soft magnetic underlayer. By proper ac erasing of the reproduced signal through the action of the underlayer (at an underlayer coercivity of Hc(u)=50 Oe) in a CoNiReP/CoB double-layered medium, the PS effect was confirmed to appear at recording densities up to about 90 kFRPI. The enhancement of the reproduced voltage at densities higher than 90 kFRPI was still observed after such ac erasure, and originates solely in the DL effect.