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US4544602A
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Magneto-optical recording medium having a ferrimagnetic recording layer
Assignee: Ricoh Co Ltd
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Filing: 1984-03-16
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Granted: 1985-10-01
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Expires: 2004-03-16
Abstract
Abstract A magneto-optical recording medium is disclosed, which comprises a transparent substrate, a vertical magnetic-anisotropic magnetic film layer formed thereon, which magnetic film layer comprises a ferrimagnetic oxide of the following formula MeGa.sub.x Fe.sub.12-x O.sub.19 wherein Me represents an element selected from the group consisting of Ba, Sr and Pb, and x is an integer of 3 to 8, and a reflection layer formed on the vertical magnetic-anisotropic film layer.
Inventors
- 👤 Hiroshi Kobayashi
- 👤 Hazime Machida
- 👤 Motoharu Tanaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:35
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/252; G11B7/254; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10589; G11B11/10591; G11B5/00; G11B5/62; G11B5/72; G11B7/242; G11B7/243; G11B2007/24302; G11B2007/24306; G11B2007/2431; G11B2007/24318; G11B2007/2432; G11B7/258; G11B7/2585; G11B7/259; G11B7/2595; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
67 words
A magneto-optical recording medium comprising a transparent substrate, a vertical magnetic-anisotropic magnetic film layer formed thereon, which magnetic film layer comprises a ferrimagnetic oxide of the following formula: MeGa.sub.x Fe.sub.12-x O.sub.19 wherein Me represents an element selected from the group consisting of Ba, Sr and Pb, and x is an integer of 3 to 8, and a reflection layer formed on said vertical magnetic-anisotropic magnetic film layer.
Claim 2
Dependent Claim
67 words
A magneto-optical recording medium comprising a transparent substrate, a vertical magnetic-anisotropic magnetic film layer formed thereon, which magnetic film layer comprises a ferrimagnetic oxide of the following formula: MeGa.sub.x Fe.sub.12-x O.sub.19 wherein Me represents an element selected from the group consisting of Ba, Sr and Pb, and x is an integer of 3 to 8, and a reflection layer formed on said vertical magnetic-anisotropic magnetic film layer.
Claim 3
Dependent Claim
31 words
A magneto-optical recording medium as claimed in claim 1, wherein said reflection layer comprises at least one element selected from the group consisting of Al, Cr, Cu, Ag, Pt and Au.
Claim 4
Dependent Claim
19 words
A magneto-optical recording medium as claimed in claim 1, further comprising a protective layer formed on said reflection layer.
Claim 5
Dependent Claim
29 words
A magneto-optical recording medium as claimed in claim 1, wherein said magnetic film layer further comprises at least one element selected from the group consisting of Sm and V.
Claim 6
Dependent Claim
33 words
A magneto-optical recording medium as claimed in claim 1, wherein said transparent substrate is made of at least one material selected from the group consisting of quartz glass, crystallized glass and transparent ceramics.
Claim 7
Dependent Claim
28 words
A magneto-optical recording medium as claimed in claim 1, wherein the thickness of said magnetic film layer is in the range of about 1,000 Å to 100,000 Å.
Claim 8
Dependent Claim
27 words
A magneto-optical recording medium as claimed in claim 1, wherein the thickness of said reflection layer is in the range of about 500 Å to 10,000 Å.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-30 | 1989-04-01 | 1989-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-30 | 1993-04-01 | 1993-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-30 | 1997-04-01 | 1997-10-01 | $7700.00 | Window Closed / Lapsed |