Claims
- 1. A magneto-optical laminated recording medium comprising:
- a substrate;
- a readable recording film supported by the substrate and having a triple loop hysteresis response to an applied magnetic field at a vicinity of the Curie temperature of the recording film, and the recording film having a single loop hysteresis response at a vicinity of room temperature.
- 2. A magnetic-optical laminated recording medium comprising:
- a substrate;
- a readable recording layer associated with the substrate and composed of rare-earth-transition metal alloy for providing a triple-loop hysteresis response in response to an applied magnetic field at a first temperature within a curie temperature range of the recording layer, the recording layer having a first magnetizable state recordable at the first temperature of the recording layer and a second magnetizable state recordable at a second temperature lower than the first temperature; and
- a ferromagnetic reflection film laminated on the recording layer.
- 3. A magneto-optical recording medium comprising:
- a substrate;
- a readable recording layer composed of a rare-earth transition metal film supported by the substrate;
- a first magnetizable state of the recording layer associated with a triple loop hysteresis response, including a central hysteresis loop and outlying hysteresis loops; the first magnetizable state recordable in response to the application of a first magnetic field strength, associated with one of said outlying hysteresis loops, at a first temperature within a range of the Curie temperature of the recording layer;
- a second magnetizable state of the recording layer distinguishable from the first magnetizable state and recordable in response to the application of a second magnetic field strength, associated with one of said outlying loops, applied within the range of the Curie temperature; said first and second magnetizable states being readable at a reading temperature less than the Curie temperature in accordance with a single loop hysteresis response of the recording layer.
- 4. The recording medium of claim 3 wherein the reading temperature comprises room temperature.
- 5. The recording medium of claim 3 wherein a ferromagnetic reflection film is laminated on the recording layer to improve the reproduction Carrier-to-Noise (CN) ratio by enhancing a Faraday effect of the recording layer.
- 6. The recording medium of claim 3 further comprising a heat control layer with a thermal conductivity within a range from approximately 0.5 to 2 watts/centimeter * degree to control heat of diffusion of the recording layer.
- 7. The recording medium of claim 3 wherein the first magnetization state has a first transition metal moment and a first rare-earth metal moment, and the second magnetization state has a second transition metal moment and a second rare-earth metal moment generally opposite the first transition metal moment and the first rare-earth metal moment, respectively.
- 8. The recording medium of claim 7 further comprising an auxiliary film magnetizable with an auxiliary magnetic moment in accordance with an external magnetic field to reduce a coercivity of the recording layer thereby permitting overwriting of the film without a previous erasing procedure.
Priority Claims (5)
Number |
Date |
Country |
Kind |
2-207525 |
Aug 1990 |
JPX |
|
2-234372 |
Sep 1990 |
JPX |
|
2-255263 |
Sep 1990 |
JPX |
|
3-174709 |
Jun 1991 |
JPX |
|
3-210430 |
Jul 1991 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 08/247,119, filed on May 20, 1994, now U.S. Pat. No. 5,639,563, which is continuation of application Ser. No. 07/740,496, filed on Aug. 5, 1991 now abandoned the entire contents of which are hereby incorporated by reference.
US Referenced Citations (21)
Foreign Referenced Citations (12)
Number |
Date |
Country |
0 257530 |
Mar 1988 |
EPX |
0 258978 |
Mar 1988 |
EPX |
368194 |
May 1990 |
EPX |
0 369610 |
May 1990 |
EPX |
606155A2 |
Jul 1994 |
EPX |
3 619618 |
Dec 1986 |
DEX |
57-169996 |
Oct 1982 |
JPX |
125950 |
Jul 1985 |
JPX |
60-231935 |
Nov 1985 |
JPX |
61-188762 |
Aug 1986 |
JPX |
63-241739 |
Oct 1988 |
JPX |
2-108256 |
Apr 1990 |
JPX |
Non-Patent Literature Citations (4)
Entry |
Hoshi et al., "Influence of O.sub.2 and N.sub.2 Addition on the Perpendicular Magnetic Anistopy of Gd-Co Amorphous Films", IAppl. Phys. 53(3); Mar. 1982; pp. 7344-7346. |
Togami et al., "Increase in Uniformity of Amorhous GdCo Films by Control of Oxygen Quantity", Jap. J. Appl. Phys. 20(8), Aug. 1981; pp. 1457-1465. |
Esho, "Perpendicular Magnetic Anisotropy in Spattered GdCo Films", J. Appl. Phys. 50(2), Feb. 1979; pp. 1606-1609. |
Heitmann et al., "Influence of Nitrogen, Oxygen and Water on Magnetic Properties of dc Magnetron Spattered GdTbFe Films", J. Appl. Phys. 61(8); Apr. 1987, pp. 3343-3345/. |
Continuations (2)
|
Number |
Date |
Country |
Parent |
247119 |
May 1994 |
|
Parent |
740496 |
Aug 1991 |
|