NUMERICAL-ANALYSIS OF LEAKAGE FIELD MODULATION FOR A NOVEL DIRECT OVERWRITE MEDIUM

The numerical calculation of the leakage field in a novel laser-power modulation direct overwrite medium has been carried out. The medium ha d four functional layers: initializing layer, biasing layer, thermal i solating layer and storage layer. The leakage field applied to the sto rage layer was changed by the laser power. The degree of leakage field change and overwritable domain width, where the direction of an effec tive field applied to the storage layer could be modulated, were obtai ned as the figures of merit for overwriting performance. Si-N and Zr-O films were chosen as the thermal isolating layer in order to change t he thermal response in the storage layer and the biasing layer. It has been found that the medium with a Si-N thermal isolating layer is sui table for overwriting and that leakage field modulation over 120 Oe wa s available within a domain width of 0.7-mu-m.