Experimental study of overwrite modulation in perpendicular magnetic recording

Perpendicular magnetic recording is regarded as next generation recording technology for storage industry. However, overwrite modulation in perpendicular recording was not thoroughly studied. In longitudinal recording, old information modulates the newly recorded transitions through in-plane field arising from write field leading edge transitions. In this study, experimental perpendicular recording overwrite tests are performed on several different perpendicular media. It shows that modulation in perpendicular recording comes directly from demagnetization field of previously recorded bits. It also shows that write head effective switching field profile significantly affects the modulation behavior.