US4385098A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic recording media
Assignee: Panasonic Holdings Corp
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Filing: 1981-11-30
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Granted: 1983-05-24
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Expires: 2001-11-30
Abstract
Abstract A magnetic recording medium of the type in which a thin magnetic film mainly comprising Co; Co and Ni; Co and Cr; or Co, Ni and Cr is deposited on a nonmagnetic substrate; the thin magnetic film comprises a native oxidized surface adjacent to the film layer at the surface and a deep layer below it; and the average oxygen content in the surface layer is greater than that in the deep layer.
Inventors
- 👤 Ryuji Sugita
- 👤 Toshiaki Kunieda
- 👤 Hideki Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:59
CPC Classifications
H; H01; H01F; H01F41/00; H01F41/14; H01F41/20; G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/72; G11B5/84; G11B5/851; H01F10/00; H01F10/08; H01F10/10; H01F10/18; H01F10/26; H01F10/265; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535; Y10T428/12583; Y10T428/1259; Y10T428/12639; Y10T428/12646; Y10T428/1266
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
86 words
A magnetic recording medium comprising a thin magnetic film having a major component selected from the group consisting of (i) cobalt, (ii) cobalt and nickel, (iii) cobalt and chromium, and (iv) cobalt, nickel and chromium disposed on a non-magnetic substrate, said thin magnetic film having a native oxidized surface, a sub-surface layer beneath and adjacent said surface, and a deep layer beneath and adjacent said subsurface layer, the average oxygen content of said subsurface layer being greater than the average oxygen content in said deep layer.
Claim 2
Dependent Claim
86 words
A magnetic recording medium comprising a thin magnetic film having a major component selected from the group consisting of (i) cobalt, (ii) cobalt and nickel, (iii) cobalt and chromium, and (iv) cobalt, nickel and chromium disposed on a non-magnetic substrate, said thin magnetic film having a native oxidized surface, a sub-surface layer beneath and adjacent said surface, and a deep layer beneath and adjacent said subsurface layer, the average oxygen content of said subsurface layer being greater than the average oxygen content in said deep layer.
Claim 3
Dependent Claim
31 words
A magnetic recording medium as set forth in claim 1, wherein the thickness of said subsurface layer is equal to about one third of the thickness of said thin magnetic film.
Claim 4
Dependent Claim
22 words
A magnetic recording medium as set forth in claim 1, wherein a plurality of thin magnetic films are overlaid over said substrate.
Claim 5
Dependent Claim
33 words
A magnetic recording medium as set forth in claim 2, wherein the average oxygen content in said subsurface layer is in excess of 1.2 times as high as that in said deep layer.
Claim 6
Dependent Claim
35 words
A magnetic recording medium as set forth in claim 1, wherein the number of oxygen atoms in said thin magnetic film is higher by 25% than the total number of metal atoms in said film.
Claim 7
Dependent Claim
27 words
A magnetic recording medium as set forth in claim 1, wherein said thin magnetic film is deposited by the vacuum evaporation process in an atmosphere containing oxygen.
Claim 8
Dependent Claim
29 words
A magnetic recording medium as set forth in claim 1, wherein said thin magnetic film is deposited in an atmosphere containing oxygen by an oblique incidence vacuum evaporation process.
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) | 1986-05-23 | 1986-11-22 | 1987-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-05-23 | 1990-11-22 | 1991-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-05-23 | 1994-11-22 | 1995-05-24 | $7700.00 | Window Closed / Lapsed |