Perpendicular Recording Characteristics Of Ring Head and Co-Cr/Co-Zr-Mo Double-Layer Media

A Winchester-type Mn-Zn ferrite ring head (gap length 0.3 ¿m) was used to evaluate the perpendicular recording/reproduction characteristics of Co-Cr/Co-Zr-Mo double-layer and Co-Cr single-layer media. The absolute reproduced output voltage was higher at high medium Hc values for the double-layer film, but there was no great difference in the D50 versus Hc characteristics of the two. Noise spikes were observed when reproducing from double-layer films after DC erasure, and was attributed to the underlayer. Except for this noise, the double-layer media exhibited more favorable characteristics.