US4588636A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1982-02-12
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Granted: 1986-05-13
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Expires: 2002-02-12
Abstract
Abstract A magnetic recording medium having a thin ferromagnetic metal film formed on a non-magnetic base by vacuum vapor deposition or ion plating is disclosed. The thin ferromagnetic metal film is based on Co and contains 0.05 to 3.0 wt % of Mg.
Inventors
- 👤 Ryuji Shirahata
- 👤 Akio Yanai
- 👤 Tatsuji Kitamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:23
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/657; G11B5/84; G11B5/851; H; H01; H01F; H01F41/00; H01F41/14; H01F41/20; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
49 words
A magnetic recording medium, comprising: a non-magnetic support base; and a thin ferromagnetic metal film formed on a surface of said base, said film being formed by vacuum vapor deposition and said film being comprised of 75 weight percent or more Co and 0.05 to 3.0 weight percent Mg.
Claim 2
Dependent Claim
49 words
A magnetic recording medium, comprising: a non-magnetic support base; and a thin ferromagnetic metal film formed on a surface of said base, said film being formed by vacuum vapor deposition and said film being comprised of 75 weight percent or more Co and 0.05 to 3.0 weight percent Mg.
Claim 3
Dependent Claim
48 words
A magnetic recording medium, comprising: a non-magnetic support base; and a thin ferromagnetic metal film formed on a surface of said base, said film being formed by ion plating and said film being comprised of 75 weight percent or more Co and 0.05 to 3.0 weight percent Mg.
Claim 4
Dependent Claim
48 words
A magnetic recording medium, comprising: a non-magnetic support base; and a thin ferromagnetic metal film formed on a surface of said base, said film being formed by ion plating and said film being comprised of 75 weight percent or more Co and 0.05 to 3.0 weight percent Mg.
Claim 5
Dependent Claim
29 words
A magnetic recording medium as claimed in claim 1, wherein said vacuum vapor deposition is carried out under a vacuum within the range of less than 5×10 -4 Torr.
Claim 6
Dependent Claim
28 words
A magnetic recording medium as claimed in any of claims 1 or 2, wherein said thin ferromagnetic metal film has a thickness from about 0.02 to 5 μm.
Claim 7
Dependent Claim
22 words
A magnetic recording medium as claimed in claim 4, wherein said ferromagnetic metal film has a thickness from 0.05 to 2 μm.
Claim 8
Dependent Claim
43 words
A magnetic recording medium as claimed in any of claims 1 or 2, wherein said thin ferromagnetic metal film contains an additional element selected from the group consisting of Fe, Ni, Si, V, Y, La, Ce, Pr, Sm, Gd, Mn, Cu, or Cr.
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) | 1989-05-12 | 1989-11-11 | 1990-05-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-12 | 1993-11-11 | 1994-05-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-12 | 1997-11-11 | 1998-05-13 | $7700.00 | Window Closed / Lapsed |