Magneto-optical recording medium, and method and apparatus for producing the same
AssigneesMatsushita Electric Industrial Co., Ltd., Canon Kabushiki Kaisha
InventorsYuuko Kawaguchi, Motoyoshi Murakami, Masahiro Birukawa, Tsutomu Shiratori, Yasuyuki Miyaoka
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Abstract
By irradiating a light beam between recording tracks of the magneto-optical recording medium, the magnetic anisotropy of at least one layer selected from the group consisting of the domain wall displacement layer and the recording layer formed between the recording tracks can be made lower than that of said layers on the recording tracks, and a bias magnetic field is applied at least between recording tracks while a light beam is radiated. Because of this, initialization of a medium may be conducted simultaneously.
Claims20
A magneto-optical recording medium, comprising a substrate and a multi-layer film formed on the substrate, the multi-layer film including a first dielectric layer, a domain wall displacement layer, a switching layer, a recording layer, and a second dielectric layer in this order from the substrate side, a Curie temperature of the switching layer being lower than those of the domain wall displacement layer and the recording layer, a domain wall in the domain wall displacement layer being displaced to a higher temperature side in a region that reaches a temperature equal to or higher than a Curie temperature of the switching layer due to irradiation with a light beam for reproduction,
- wherein magnetic anisotropy of at least one layer selected from the group consisting of the domain wall displacement layer and the recording layer formed between recording tracks is made lower than that of said layers on the recording tracks, and magnetization of at least one magnetic layer selected from the group consisting of the domain wall displacement layer, the switching layer, and the recording layer is aligned in a predetermined direction in a region that is a half or more of a track width in a track width direction in at least a part of the recording tracks.
A method for producing a magneto-optical recording medium including a substrate and a multi-layer film formed on the substrate, the multi-layer film including a first dielectric layer, a domain wall displacement layer, a switching layer, a recording layer, and a second dielectric layer in this order from the substrate side, wherein a Curie temperature of the switching layer is lower than those of the domain wall displacement layer and the recording layer, and a domain wall in the domain wall displacement layer is displaced to a higher temperature side in a region that reaches a temperature equal to or higher than a Curie temperature of the switching layer due to irradiation with a light beam for reproduction, the method comprising:
- irradiating a light beam between the recording tracks of the magneto-optical recording medium, thereby making magnetic anisotropy of at least one layer selected from the group consisting of the domain wall displacement layer and the recording layer formed between the recording tracks lower than that of said layers on the recording tracks;
- and
- applying a bias magnetic field while irradiating the light beam at least between the recording tracks.
An apparatus for producing a magneto-optical recording medium including a substrate and a multi-layer film formed on the substrate, the multi-layer film including a first dielectric layer, a domain wall displacement layer, a switching layer, a recording layer, and a second dielectric layer in this order from the substrate side, wherein a Curie temperature of the switching layer is lower than those of the domain wall displacement layer and the recording layer, and a domain wall in the domain wall displacement layer is displaced to a higher temperature side in a region that reaches a temperature equal to or higher than a Curie temperature of the switching layer due to irradiation with a light beam for reproduction, the apparatus comprising:
- a light beam irradiation apparatus for irradiating a light beam between recording tracks of the magneto-optical recording medium;
- a magnetic field application apparatus for applying a bias magnetic field at least between the recording tracks while irradiating the light beam;
- and
- a magnetic field control apparatus for changing a direction of the bias magnetic field.
Dependencies are inferred from the claim text.