US4497870A
Expired / Lapsed
US
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Magneto-optical recording medium
Assignee: Panasonic Holdings Corp
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Filing: 1983-04-06
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Granted: 1985-02-05
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Expires: 2003-04-06
Abstract
Abstract A magneto-optical recording medium comprising a layer of amorphous rare-earth-transition-metal alloy having a uniaxial magnetic anisotropy, the alloy containing germanium as additive, and the recording medium having high crystallization temperature, enough stability and good reading S/N ratio.
Inventors
- 👤 Yoshihiko Kudo
- 👤 Hidetsugu Kawabata
- 👤 Masahiro Birukawa
- 👤 Noriaki Hara
- 👤 Akira Muto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:35
CPC Classifications
H; H01; H01F; H01F10/00; H01F10/08; H01F10/10; H01F10/12; H01F10/13; H01F10/133; H01F10/135; G; G03; G03G; G03G5/00; G03G5/16; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
93 words
A magneto-optical recording medium comprising a magneto-optical recording medium having a high crystallization temperature, high stability and excellent signal-to-noise characteristics suitable for thermo-magnetic recording and magneto-optical reading, said recording medium comprising a non-magnetic substrate having thereon at least one layer of an amorphous rare-earth-3d-transition-metal alloy having a uniaxial magnetic anisotrophy, wherein said alloy has a composition expressed by the general formula: (R.sub.x M.sub.1-x).sub.1-y Ge.sub.y wherein R is at least one rare-earth metal, M is at least one 3d transition metal, and X and Y are in the ranges of 0.1<x<0.4 and 0<y<0.2, respectively.
Claim 2
Dependent Claim
93 words
A magneto-optical recording medium comprising a magneto-optical recording medium having a high crystallization temperature, high stability and excellent signal-to-noise characteristics suitable for thermo-magnetic recording and magneto-optical reading, said recording medium comprising a non-magnetic substrate having thereon at least one layer of an amorphous rare-earth-3d-transition-metal alloy having a uniaxial magnetic anisotrophy, wherein said alloy has a composition expressed by the general formula: (R.sub.x M.sub.1-x).sub.1-y Ge.sub.y wherein R is at least one rare-earth metal, M is at least one 3d transition metal, and X and Y are in the ranges of 0.1<x<0.4 and 0<y<0.2, respectively.
Claim 3
Dependent Claim
15 words
The magneto-optical recording medium of claim 1 in which the value of y is 0<y<0.15.
Claim 4
Dependent Claim
65 words
The magneto-optical recording medium comprising a magneto-optical recording medium having a high crystalline temperature, high stability and excellent signal-to-noise characteristics suitable for thermo-magnetic recording and magneto-optical reading, said recording medium comprising a non-magnetic substrate having thereon at least one layer of an amorphous rare-earth-3d-transition-metal alloy having a uniaxial magnetic anisotrophy in which said alloy is: (Gd.sub.0.13 Tb.sub.0.13 Fe.sub.0.74).sub.1-y Ge.sub.y and y has the value 0<y≦0.15.
Claim 5
Dependent Claim
65 words
The magneto-optical recording medium comprising a magneto-optical recording medium having a high crystalline temperature, high stability and excellent signal-to-noise characteristics suitable for thermo-magnetic recording and magneto-optical reading, said recording medium comprising a non-magnetic substrate having thereon at least one layer of an amorphous rare-earth-3d-transition-metal alloy having a uniaxial magnetic anisotrophy in which said alloy is: (Gd.sub.0.13 Tb.sub.0.13 Fe.sub.0.74).sub.1-y Ge.sub.y and y has the value 0<y≦0.15.
Claim 6
Dependent Claim
24 words
A magneto-optical recording medium according to claim 3 in which said alloy has a crystallization temperature (T K ) at least about 350° C.
Claim 7
Dependent Claim
31 words
A magneto-optical recording medium according to claim 3 in which said alloy has a S/N ratio of between about 1 and 1.5 times a magneto-optical recording medium devoid of said alloy.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-02-05 | 1988-08-06 | 1989-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-05 | 1992-08-06 | 1993-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-05 | 1996-08-06 | 1997-02-05 | $7700.00 | Window Closed / Lapsed |