Write/erase cyclability of TbFeCo for mark edge recording

Domain size changes due to thermal relaxation after high laser power irradiation on amorphous TbFeCo films were studied. In order to achieve mark edge recording for high‐density magneto‐optical memory, accurate domain size recording is required even after a million erase/write cycles. Highly accelerated erase/write test was performed on typical recording media, rare‐earth (RE) ‐rich and transition‐metal (TM) ‐rich disks. The elongation of the domain size written on the TM‐rich film after erase/write cycles was clearly evident; however, the change in the domain size of RE‐rich films was small. The small domain size change of the RE‐rich disk can be explained in terms of the rapid increase in the coercive force with decreasing temperature and the smaller domain‐wall driving force at recording temperature than those for the TM‐rich disk, even though both have the same level of structural relaxation.