Characteristics of Repeated Writing on MnBi Magneto-Optical Disks

Repeated write and erase characteristics of quadrilayer MnBi magnetooptic disks were measured. The carrier level decreased with the number of write cycles. We found that this degradation was caused by decomposition of the MnBi low-temperature phase and by the change from the low-temperature phase to the high-temperature phase in the writing process. The rates of decomposition and phase change decreased at higher linear velocities and lower write powers. The reliability of the MnBi write cycle can be improved by optimization of the disk's thermal structure and recording conditions.