Magnetic printing technique for longitudinal thin film media with high coercivity of 6000 Oe

A magnetic printing technique was satisfactorily demonstrated for longitudinal hard-disk media with coercivity of 3000 Oe, in which soft magnetic patterns formed on a master disk as servo signals were magnetically transferred onto the media. The magnetic field (the printing field) applied to the master disk during the printing process is required to be as high as the coercivity of the media, which increases as the areal density of the hard-disk drive increases. However, high printing fields have been reported to cause magnetic saturation of the patterns and extraneous subpulses due to that saturation. This article addresses the issue of whether magnetic printing for media with high coercivity can be satisfactorily carried out. We observed playback signals from printed media with different coercivities ranging up to 6450 Oe and demonstrated that the magnetic printing technique for media with coercivity of up to 6000 Oe was satisfactorily implemented.