Abstract
Repeated writing and erasing characteristics were measured on quadrilayer MnBi magneto-optical disks. The carrier levels decreased with the number of writing cycles. We found that this degradation was caused by decomposition of the MnBi lowtemperature phase and by the change from the lowtemperature phase to the high-temparature phase in the writing process. The rates of decomposition and phase change decreased at a high linear velocity and alow write power. The reliability of the MnBi writing cycle can be improved by optimization of the disk's heat structure and recording conditions.
