| 摘要 |
PURPOSE:To eliminate the influence of the leakage magnetic field of an actuator, etc., of an optical head and to realize a stable over-write state, by producing a magnetic field opposite to the leakage magnetic field in the same size as this magnetic field by a magnetic head and limiting an effective magnetic field on the magnetic film surface only to the modulated magnetic field applied by the magnetic head. CONSTITUTION:The output of a semiconductor laser 1 is increased in comparison with that set in a reproduction and a light spot is radiated to a magnetic film 7b in terms of DC to raise the temperature of the part irradiated by the light spot. At the same time, a current modulated in accordance with the information to be recorded is supplied to a magnetic head 8 and a modulated magnetic field is applied onto the film 7b. Thus the magnetization of the film 7b is inverted in response to the vertical direction of the modulated magnetic field. That is, the effective magnetic field intensity of the recording threshold value is approximately at zero with a bias magnetic field -Ha applied by the head 8. Then the modulated magnetic field is applied centering on the effective magnetic field intensity 0. Thus the stable recording/erasing actions are carried out.
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