High Performance Magneto-Optical Disk Using A New Plastic Substrate

To realize high data rate and high reliability 5.25 inch Magneto-Optical(MO) disks, suitable materials for a tri-layer structure(substrate/Kerr enhancement layer/magnetic layer/protective layer) and substrates were studied. By optimizing the composition of TbFeCo film, micron-size and regular-shaped recorded domains were obtained. SiNx film showed enough Kerr rotation enhancement and good protectivity to be used as an enhancement layer and a protective layer for a TbFeCo magnetic film. Those films were constructed on newly developed plastic substrates of photocurable casting resin(PHC) which have as low retardation and as high heat-resistance as glass/2p(photo-polymerization) substrates. MO disks with the tri-layer structure on PHC showed high reliability even in severe circumstances.