Structures and Dynamic Characteristics of Magneto-Optical Disk

Changes with time are reported in the reflection factor, magneto-optical rotation angle, coercive force, C/N, and error rate of magneto-optical disks with four different structures (A-D) on PMMA substrates, at 45°C and 55°C and humidities of 90 and 60 percent. Disks of structure A, without a protective film between substrate and medium, showed rapid deterioration of properties; structures C and D tended to develop cracks, making measurements impossible. Structure B disks were estimated to have a service lifetime of 4 to 6 years at 25°C and 50% RH; for longer lifetimes, PC or glass substrates are desired.