Understanding overwrite for high speed recording

Abstract

In thin film disk recording, head field rise time determines the growth speed of the recording bubble[]]. When the medium speed becomes comparable to the bubble growth, the effectively reduced head field gradient results in broadening of the recorded transition. When the medium speed becomes greater than the bubble growth speed, the transition can he actually recorded at where the head field gradient is poor. That will result in more severe demagnetization field induced transition shift. In this study, by correlating hard trmsition shift and transition broadening with write current waveform and rise time, a understanding of overwrite degradation mechanism at high medium speed is obtained.