EP0257530A2
Expired / Lapsed
EP
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Thermo-magnetic recording method applying power modulated laser on magnetically coupled double layer structure of perpendicular anisotropy film
Assignee: Sony Corp
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Filing: 1987-08-18
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Granted: —
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Expires: 2007-08-18
Abstract
Abstract Thermomagnetic recording method using a thermomagnetic recording medium having a superposed layer (5) of magnetically coupled first and second magnetic thin films (3,4) is disclosed.The magnetic thin film includes a portion where the respective magnetic moments of the first and second thin films are coupled in opposite directions to each other(mode C). The method comprises heating the superposed layer in a first heating state in which the superposed layer (5) is heated at a temperature T₁ which is higher than the Curie temperature T C1 of the first magnetic thin film (3) and will not cause the inversion of the magnetic moment of the second magnetic thin film (4) or in a second heating state in which the superposed layer (5) is heated at a temperature T₂ which is higher than the Curie temperature T C1 and is high enough to cause the inversion of the magnetic moment of the second magnetic thin film (4) by modulating heating condition according to an information signal to be recorded; and forming recording magnetization on the thermomagnetic recording medium by cooling the heated superposed layer of the thermomagnetic recording medium. In the method, real-time overwriting information can be achieved without using a modulated external magnetic fieled.
Inventors
- 👤 Katsuhisa Aratani
- 👤 Tomiji Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 15:23
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/03; G11B11/10; G11B11/105; G11B11/10502; G11B11/10515; G11B11/10504; G11B11/10506; G11B11/10517; G11B11/10519; G11B11/10521; G11B11/10582; G11B11/10586
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
148 words
Thermomagnetic recording method using a thermomagnetic recording medium having a superposed layer (5) of magnetically coupled first and second magnetic thin films(3,4),which comprises: heating said layer in a first heating state in which said layer is heated at a temperature T₁ which is higher than Curie temperature T C1 of said first magnetic film (3) and will not cause the inversion of magnetic moment of said second magnetic thin film (4) and in a second heating state in which said layer is heated at a temperature T₂ which is higher than the Curie temperature T C1 and is high enough to cause the inversion of magnetic moment of said second magnetic thin film(4) said first and second heating states being modulated according to an information signal to be recorded; and forming recording magnetization on the thermomagnetic recording medium by cooling the heated layer of said thermomagnetic recording medium.
Claim 2
Dependent Claim
148 words
Thermomagnetic recording method using a thermomagnetic recording medium having a superposed layer (5) of magnetically coupled first and second magnetic thin films(3,4),which comprises: heating said layer in a first heating state in which said layer is heated at a temperature T₁ which is higher than Curie temperature T C1 of said first magnetic film (3) and will not cause the inversion of magnetic moment of said second magnetic thin film (4) and in a second heating state in which said layer is heated at a temperature T₂ which is higher than the Curie temperature T C1 and is high enough to cause the inversion of magnetic moment of said second magnetic thin film(4) said first and second heating states being modulated according to an information signal to be recorded; and forming recording magnetization on the thermomagnetic recording medium by cooling the heated layer of said thermomagnetic recording medium.
Claim 3
Dependent Claim
226 words
Thermomagnetic recording method using a thermomagnetic recording medium having a superposed magnetic film (5) of magnetically coupled first and second magnetic thin films (3,4) which comprises: modulating mode of heating said magnetic film between a first heating state in which said magnetic film is heated at a temperature T₁ which is higher than the Curie temperature T C1 of the first magnetic thin film (3) and will not cause the inversion of the sublattice magnetization of the second magnetic thin film (4) and a second heating state in which said magnetic film is heated at a temperature T₂ which is higher than the Curie temperature T C1 and is high enough to cause the inversion of the sublattice magnetization of said second magnetic thin film (4) having a compensation temperature between the room temperature and the temperature T₂ according to an information signal to be recorded; forming a magnetic record on the thermomagnetic recording medium by cooling the laminated magnetic film from the heating state to make the direction of the sublattice magnetization of said first magnetic thin film the same as the direction of the sublattice magnetization of said second magnetic thin film(4) by the exchange energy of said first and second magnetic thin films; and cooling said magnetic film to the room temperature to invert the sublattice magnetization of said second magnetic thin film.
Claim 4
Dependent Claim
226 words
Thermomagnetic recording method using a thermomagnetic recording medium having a superposed magnetic film (5) of magnetically coupled first and second magnetic thin films (3,4) which comprises: modulating mode of heating said magnetic film between a first heating state in which said magnetic film is heated at a temperature T₁ which is higher than the Curie temperature T C1 of the first magnetic thin film (3) and will not cause the inversion of the sublattice magnetization of the second magnetic thin film (4) and a second heating state in which said magnetic film is heated at a temperature T₂ which is higher than the Curie temperature T C1 and is high enough to cause the inversion of the sublattice magnetization of said second magnetic thin film (4) having a compensation temperature between the room temperature and the temperature T₂ according to an information signal to be recorded; forming a magnetic record on the thermomagnetic recording medium by cooling the laminated magnetic film from the heating state to make the direction of the sublattice magnetization of said first magnetic thin film the same as the direction of the sublattice magnetization of said second magnetic thin film(4) by the exchange energy of said first and second magnetic thin films; and cooling said magnetic film to the room temperature to invert the sublattice magnetization of said second magnetic thin film.
Claim 5
Independent Claim
134 words
A method of reproducing signals recorded in a thermomagnetic recording medium having a superposed magnetic film(5) formed by magnetically coupled first and second magnetic thin films (3,4) and having a recording part where the respective direction of the respective magnetic moments of said first and second magnetic thin films are opposite to each other and a recording part where the respective directions of the respective magnetic moments of the first and second magnetic thin films are the same, comprising: applying a magnetic field to said magnetic film so that the respective directions of the respective magnetic moments of the first and second magnetic thin films are turned in the same direction prior to reading signals from said magnetic film: and reproducing signals from said laminated magnetic thin film by means of a magnetooptic effect.
Claim 6
Independent Claim
134 words
A method of reproducing signals recorded in a thermomagnetic recording medium having a superposed magnetic film(5) formed by magnetically coupled first and second magnetic thin films (3,4) and having a recording part where the respective direction of the respective magnetic moments of said first and second magnetic thin films are opposite to each other and a recording part where the respective directions of the respective magnetic moments of the first and second magnetic thin films are the same, comprising: applying a magnetic field to said magnetic film so that the respective directions of the respective magnetic moments of the first and second magnetic thin films are turned in the same direction prior to reading signals from said magnetic film: and reproducing signals from said laminated magnetic thin film by means of a magnetooptic effect.
References Cited (Backward Citations)
EP0051296A1
Cited
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