NOVEL COMPOSITE PERPENDICULAR RECORDING MEDIUM WITH CO78CR22 OVER CR-RICH CO72CR28 FOR MERGED MR HEADS

We propose a new type of composite perpendicular medium consisting of a 50-nm-thick Co78Cr22 upper layer and a 50-nm-thick Cr-rich Co72Cr28 lower layer for magnetic recording systems using MR heads. The lower C r-rich layer, with strong magnetic interaction in the perpendicular di rection and good crystalline orientation, contributes to the high reso lution and high signal-to-noise ratio (S/N). The upper layer, with lar ge saturation magnetization (M-s) and large anisotropy field (H-K perp endicular to) plays a major role in increasing the signal amplitude. M agnetic recording characterization using this medium and a merged MR h ead yielded a D-50 Of 140 kFCI, an S/N of 33.4 dB, and a signal amplit ude of 411 mu V-pp at 100 kFCI with a 62-nm magnetic spacing.