抄録
Optical enhancement conditions and read/write characteristics for exchange-coupled double-layer magneto-optical (MO) disks were investigated. It was found that the figure of merit (R(1/2)·θk) for an MO disk with a thick (60-nm) magnetic layer is comparable with that for a conventional MO disk with a thin (20-nm) magnetic layer, The writing noise level of the thick-magnetic-layered MO disk is markedly lower (2∼5dB) than that of the conventional one. An exchange-coupled double-layer (GdFeCo30-nm/TbFeCo30-nm) MO disk, which has a large Kerr rotation, moderate reflectivity, and low noise level, is suitable as a high-performance medium.
This MO disk shows a C/N ratio of 45 dB for a wavelength of 680 nm, and a mark length of 0.67 μm when a 1.2-μm track pitch polycarbonate substrate is used.
