Experimental study of overwrite mechanism in perpendicular recording

In this paper, we present an experimental study of the overwrite mechanism in perpendicular recording, utilizing a scanning contact recording tester. It is found when writing new data over existing old data in a Stoner-Wohlfarth like perpendicular medium, the on-track remanence level (the regions between two adjacent transitions) of the new transitions is modulated by the old data pattern. This is because of the relatively poorer effective write field in the middle of the pole-tip footprint. It is argued that the demagnetization field from the residual magnetization pattern underneath the middle of the pole-tip region significantly affects the writing at the trailing edge, resulting in the observed modulation The phenomenon becomes less pronounced when the magnetic reversal becomes less dependent on the field angle.