| 摘要 |
PURPOSE:To shift the bit information to a prescribed position with high stability by forming a cylindrical magnetic domain magnetized reverse to the magnetizing direction of a bias magnetic field at a prescribed position in a magnetized film and then irradiating the light to said magnetic domain with such a level of intensity that can produce a difference of temperatures between both ends of the magnetic domain. CONSTITUTION:A medium 1 is fixed in a loadable/unloadable way to a bias magnetic field generating means 2 consisting of a permanent magnet, and a bias magnetic field is always applied to the entire surface of the medium 1 especially at an oxide film 1b. The medium 1 and therefore the magnetic field generator 2 can be shifted by a motor 3, and at the same time an auxiliary bias coil 4 is set at the periphery of the medium 1 to increase the bias magnetic field when necessary. The laser light given from an argon laser of a light generator 5 is led into an optical modulator 6 for the medium 1 and then extracted in the form of the pulse light. This pulse light is made incident to a lens 9 via a polarizer 7 and a half mirror 8 to form a bit. Then the pulse light of 5.0mus width is irradiated at a position distant away from the recording bit by a distance xmum to measure the minimum laser power with which the bit can be shifted to the position irradiated by the pulse light. If x approx.<5mum is satisfied, the bit can be shifted with high accuracy with irradiation of the pulse light larger than the minimum power. |
