发明授权
US5355354A Non-overwritable magnetooptical recording apparatus using exchange-coupled two-layered medium with interface magnetic wall 失效
不可覆写的磁光记录装置,使用具有界面磁壁的交换耦合双层介质

  • 专利标题: Non-overwritable magnetooptical recording apparatus using exchange-coupled two-layered medium with interface magnetic wall
  • 专利标题(中): 不可覆写的磁光记录装置,使用具有界面磁壁的交换耦合双层介质
  • 申请号: US48178
    申请日: 1993-04-20
  • 公开(公告)号: US5355354A
    公开(公告)日: 1994-10-11
  • 发明人: Hiroyuki MatsumotoJun Saito
  • 申请人: Hiroyuki MatsumotoJun Saito
  • 申请人地址: JPX Tokyo
  • 专利权人: Nikon Corporation
  • 当前专利权人: Nikon Corporation
  • 当前专利权人地址: JPX Tokyo
  • 优先权: JPX2-154288 19900613; JPX2-172237 19900629
  • 主分类号: G11B11/105
  • IPC分类号: G11B11/105 G11B13/04
Non-overwritable magnetooptical recording apparatus using
exchange-coupled two-layered medium with interface magnetic wall
摘要:
A non-overwritable recording apparatus comprises a magnetooptical recording media including at least first and second exchange-coupled layers having perpendicular magnetic anisotrophy, the Curie temperature of the second layer being higher than that of the first layer. The direction of magnetization of the second layer is aligned in a predetermined direction, without changing the direction of magnetization of the first layer, and the direction of magnetization of the first layer is aligned in a direction such that an interface magnetic wall is formed between the first and second layers in at least each recording portion of the medium. While the medium is rotated, a laser beam is radiated on the medium and is pulse-modulated, according to information to be recorded, between a first intensity level which imparts to a recording portion a temperature at least as high as the Curie temperature of the first layer and lower than that of the second layer and which thereby forms a mark having no interface magnetic wall between said first and second layers, and a second intensity level, including zero-level, which imparts to a recording portion a temperature lower than a lowest temperature at which the interface magnetic wall disappears, whereby the mark is not formed. In a modification, the first intensity level imparts to a recording portion a temperature lower than the Curie temperature of the first layer and at least as high as a lowest temperature at which an interface magnetic wall between the first and second layers disappears.
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