MAGNETO-OPTIC RECORDING MEDIUM AND MANUFACTURING METHOD

摘要

A magneto-optic recording medium has a recording layer for storing information and an initializing layer which is uniformly magnetized in a fixed direction during the manufacturing process. The medium is directly overwritable by modulation of a laser beam between two power levels. In low writing, the recording layer is heated sufficiently to acquire the magnetization of the initializing layer by means of exchange coupling between the layers. In high writing, the recording layer is heated to a higher temperature, above its Curie temperature, and is magnetized in the opposite direction by an external bias magnet. Additional magnetic layers may be provided between the recording and initializing layers to facilitate high writing. Since the initializing layer is always magnetized in the same direction, no external initializing magnet is required.