Direct and reverse overwrite processes in perpendicular recording

Excellent overwrite (OVW) performance has to be guaranteed for two cases, namely, the case where a low frequency (LF) background data pattern is overwritten by a high frequency (HF) data pattern and the reverse case, e.g., the reverse overwrite (ROVW) situation where a high linear density background pattern is overwritten by a low linear density data pattern. In this work, the spectra of both OVW and ROVW processes have been investigated experimentally to identify the intrinsic characteristics of residual noise in the OVW and ROVW processes in perpendicular recording. Specifically the spectra of both OVW and ROVW processes have been quantitatively analyzed to quantify the characteristics of relevant amplitude modulation or amplitude cancellation process.