RECORDING ON CO/PT MAGNETOOPTICAL DISKS USING A 488-NM WAVELENGTH LASER

Co/Pt multilayer disks with a double-layer and a quadri-layer structure were prepared on a 2 P (photopolimerized) glass substrate with 1-mu-m-pitched grooves. The read/write characteristics of the disks were studied using Ar gas laser at a wavelength of 488 nm. It was confirmed that very small domains 0.3-mu-m in length were stably recorded. The carrier-to-noise ratio was 29 and 32 dB (30 kHz BW) at a mark length of 0.3-mu-m for double-layer and quadri-layer disks, respectively, being larger than that measured for a TbFeCo disk because of a higher figure of merit. In higher-density recording below 0.5-mu-m mark length, a quadri-layer disk shows a larger recording power margin than a double-layer disk due to the smaller expansion of domain with power, originating from the sharper thermal distribution.