Recording Properties of Magneto-Optical Disks with Metal Guiding Layers

The track pitch of magnetooptical disks with metal guiding layers was reduced to less than the laser spot size by suppressing crosstalk. The recorded domain width was effectively confined by the width of the spiral-shape recording region from which the guiding layer was removed. The CNR was improved by using a substrate/enhancing layer/guiding layer/interference layer/recording layer structure. The total thickness of the enhancing and interference layers was adjusted in order to increase the Kerr effect enhancement, and a CNR of 47.1 dB at 3.73 MHz was obtained for a track pitch of 1.0 ¿m. Low crosstalk values of less than ¿28.8 dB and ¿26.2 dB were achieved at 1.0 MHz for track pitches of 1.0 and 0.9 ¿m respectively, using a conventional optical head having an objective lens of 0.53 NA and a 780 nm laser.