Dependence of Recording and Reproducing Characteristics on Thickness of Co-Cr Layer in Perpendicular Recording

The influence of the thickness of the Co-Cr layer in a Co-Cr/Ni-Fe double-layer medium on the recording and reproducing characteristics, was investi- gated by computer simulation. In practice, perpendicular media with a relatively thin Co-Cr layer, about 0.1¿m thick, but still thicker than in longitudinal media, produced high playback voltages at high densities. This is because the sharp magnetic field distrib- ution of a single-pole head is created for a thin Co-Cr layer by enhancing the head-to-medium magnetic coupling. As a result, the large residual magnetization remains in the recording process, and the high resolution of the single-pole head generates high playback voltages even at high densities.