QUASIPERPENDICULAR MAGNETIC RECORDING ON A COMPOSITE MEDIUM WITH CO-CR PERPENDICULAR AND FE-CO LONGITUDINAL LAYERS

Quasiperpendicular magnetic recording on a perpendicular anisotropy Co-Cr medium with a very thin semihard back layer having longitudinal magnetization has been investigated. When the back layer was introduced, the Co-Cr media began to show single peak pulses and an enhanced output due to reduced demagnetization. A higher factor of improvement in the output was obtained for a Co-Cr layer with a lower coercivity. A dominant factor to determine the recording density limit was the head gap length. A recording density D50 of 125 kFRPI with overwrite of 30 dB can be achieved for a short gap of 0.15-mu-m when a MIG-type head was used. It is concluded that the composite medium has practical advantages for a hard-disk system as well as a video tape system.