Recording characteristics of perpendicular hard disk media measured by MIG head.

Abstract

Recording and reproducing characteristics of a Co-Cr perpendicular magnetic hard disk with a thin Fe-Co back layer were investigated by non-flying type MIG head. The Co-Cr/Fe-Co composite media were made by R.F. sputtering on glass substrate with Cr underlayer. Results show that a reproduced isolated pulse of the medium has a single peak with a large amplitude. The head gap length was a dominant factor to the upper limit of the recording density. Using a MIG head whose gap length is 0.15 μm, D₅₀ of 120 kFRPI and normalized output of 95 nV_0-p/μm · turn · m/s can be achieved. Furthermore, when the thickness of Co-Cr layers was increased, the output voltage became larger, but Over-Write characteristics