Recording Characteristics of Perpendicular Hard Disk Media Measured by MIG Head

Recording and reproducing characteristics of a Co-Cr perpendicular magnetic hard disk with a thin Fe-Co back layer were investigated using a non-flying type MIG head. The Co-Cr/Fe-Co composite media were prepared by rf sputtering onto glass substrate with a Cr underlayer. The results showed that a reproduced isolated pulse from the medium has a single peak with large amplitude. The head gap length was a dominant factor determining the upper limit of the recording density. Using a MIG head with a gap length of 0.15 μm, a D
₅₀
of 120 kFRPI and normalized output of 95 nV
_0-p
/μm-turn-m/s can be achieved. Furthermore, when the thickness of the Co-Cr layer was increased, the output voltage grew larger, but the overwrite characteristic deteriorated.