Stability of Recording Sensitivity on MO Disks at Low Linear Velocities

Rewritable compact discs (CDs) using magnetooptical (MO) materials have been developed. The disks were prepared by depositing Si3N4, TbFeCo alloy, Si3N4 and Al films on polycarbonate substrates using a magnetron sputtering system. Sputter etching was carried out for the Si3N4 layer proir to depositing the magnetic layer, with the very interesting result that the external magnetic field sensitivity was improved. The stability of the write power and magnetic field sensitivity of the above MO disks was investigated. This paper reports the relation between the recording sensitivity stability and the sputter etching effect.