| 摘要 |
PURPOSE:To enable overwriting in a photomagnetic recording medium by regulating the direction of residual magnetic field whether the heating of a magnetic layer is performed or not by changing the intensity of heating at the time of writing by laser light. CONSTITUTION:When making writing magnetization in the same direction with the magnetic field H of a thin film magnet 2 in a recording layer 5, laser light 9 is projected on the place of writing of the recording layer 5 and heated. Coercive force is lowered by the temperature to Hr1, and becomes Hr1<H1-H0, and heated until magnetization is inverted. When magnetizing the recording layer 5 in the direction reverse to the magnetic field H of the thin film magnet 2, that is, H0 direction, laser light stronger than the case of H1 direction writing is projected for heating on the place of writing of the recording layer 5 and on the thin film magnet 2 at the back through it. The recording layer 5 and the thin film magnet 2 are heated until coercive force of the recording layer 5 and the magnetic field due to the thin film magnet 2 are lowered to Hr0 and H1r respectively and made to H0>H1r, Hr0<H0-H1r and the magnetization of the recording layer 5 is inverted. Thereby, overwriting on a photomagnetic recording medium is made possible. |
