MFM analysis of recorded bit patterns of perpendicular media

Read/write characteristics of a perpendicular double-layered medium with va rious thicknesses of soft magnetic layer delta (soft) using a ring head wer e investigated by analyzing the MFM image of the recorded bit pattern and r eproduced waveform. It was found that the recording bits were written by th e field of the head gap for tire medium with delta (soft) of 20 nm and whol e plane of the write pole for the medium with delta (soft) of 200 nm. It wa s also found that the bit pattern is disturbed by re-writing in recorded do main for the medium with delta (soft) of 20 nm and the track width expands for the medium with delta (soft) of 200 nm because of the effect of the hea d skew angle. The SNR of the medium with delta (soft) of 200 nm was 5 dB hi gher than that with delta (soft) 20 nm at a bit length of 0.5 mum. (C) 2001 Elsevier Science B.V. All rights reserved.