US4287225A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process of making a magnetic recording medium
Assignee: Emtec Magnetics GmbH
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Filing: 1980-03-03
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Granted: 1981-09-01
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Expires: 2000-03-03
Abstract
Abstract A magnetic recording medium comprising a non-magnetic base which is dimensionally stable at up to 300° C., and an 0.03-0.4 μm thick magnetically hard recording layer of an Sm-Co alloy, vacuum-deposited thereon, which layer possesses uniaxial magnetic anisotropy in the plane of the layer, and a process for the manufacture of this recording medium.
Inventors
- 👤 Eckhart Kneller
- 👤 Roland Koenig
- 👤 Eberhard Koester
- 👤 Werner Grau
- 👤 Dieter Mayer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:45
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/656; H; H01; H01F; H01F10/00; H01F10/08; H01F10/10; H01F10/12; H01F10/13; H01F10/133; H01F10/135; H01F10/137; H01F41/00; H01F41/14; H01F41/20; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12472; Y10T428/12493; Y10T428/12736; Y10T428/1275; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
114 words
A process for the manufacture of a magnetic recording medium by vacuum-depositing a recording layer of an Sm-Co alloy onto a non-magnetic base which is dimensionally stable at up to 300° C., wherein the recording layer consists of an amorphous Sm-Co x alloy, where x is from 1 to 20, possesses uniaxial magnetic anisotropy in the plane of the layer and has a coercive force of from 10 to 100 kA/m and a squareness ratio of more than 0.9, and the surface of the base is provided, parallel to the intended uniaxial anisotropy, with groove-shaped depressions having a depth of from 0.03 to 0.4 μm, at a spacing of from 10 to 200 μm.
Claim 2
Dependent Claim
114 words
A process for the manufacture of a magnetic recording medium by vacuum-depositing a recording layer of an Sm-Co alloy onto a non-magnetic base which is dimensionally stable at up to 300° C., wherein the recording layer consists of an amorphous Sm-Co x alloy, where x is from 1 to 20, possesses uniaxial magnetic anisotropy in the plane of the layer and has a coercive force of from 10 to 100 kA/m and a squareness ratio of more than 0.9, and the surface of the base is provided, parallel to the intended uniaxial anisotropy, with groove-shaped depressions having a depth of from 0.03 to 0.4 μm, at a spacing of from 10 to 200 μm.
Claim 3
Dependent Claim
25 words
A process for the manufacture of a magnetic recording medium as claimed in claim 1, wherein the groove-shaped depressions are arranged concentrically to one another.
Claim 4
Dependent Claim
29 words
A process for the manufacture of a magnetic recording medium as claimed in claim 2, wherein the base is kept at from 20° to 300° C. during vacuum deposition.
Claim 5
Dependent Claim
40 words
A process for the manufacture of a magnetic recording medium as claimed in claim 1, wherein, during vacuum deposition, the base is in a substantially uniform magnetic field of more than 5 kA/m, applied parallel to the intended uniaxial anisotropy.
Claim 6
Dependent Claim
29 words
A process for the manufacture of a magnetic recording medium as claimed in claim 4, wherein the base is kept at from 20° to 300° C. during vacuum deposition.
Claim 7
Dependent Claim
29 words
A process for the manufacture of a magnetic recording medium as claimed in claim 1, wherein the base is kept at from 20° to 300° C. during vacuum deposition.
References Cited (Backward Citations)
US3615911A
Cited
GB1379360A
Cited
US3970433A
Cited
US4069360A
Cited
US4074016A
Cited
US4152487A
Cited
DE2658956A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-08-31 | 1985-03-02 | 1985-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-31 | 1989-03-02 | 1989-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-31 | 1993-03-02 | 1993-09-01 | $7700.00 | Window Closed / Lapsed |