Recording on Co/Pt magneto‐optical 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‐μm‐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 μm 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 μm 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‐μm 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.