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Patent US4801500A successfully refreshed from Google Patents.
US4801500A
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Magnetic recording medium
Assignee: Fujifilm Holdings Corp
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Filing: 1987-12-16
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Granted: 1989-01-31
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Expires: 2007-12-16
Abstract
Abstract A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a thin ferromagnetic metal film, wherein the thin ferromagnetic metal film contains an iron atom, a nitrogen atom and an oxygen atom within the following atomic percent ranges: 57≦a≦90 2≦b≦20 5≦c≦23 b+c<25 in which a, b and c represent the percentage of iron atom, nitrogen atom and oxygen atom, respectively, based on the total of these atoms in the thin ferromagnetic metal film.
Inventors
- 👤 Tadashi Yasunaga
- 👤 Akio Yanai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:22
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/658; 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
70 words
A magnetic recording medium comprising a non-magnetic support having provided thereon a thin ferromagnetic metal film, wherein the thin ferromagnetic metal film comprises iron, nitrogen and oxygen atoms within the following atomic percent ranges: 57≦a≦90 2<b<20 5<c<23 b+c<25 in which a, b and c represent the percentage of iron nitrogen and oxygen atoms, respectively, based on the total of iron, nitrogen and oxygen atoms in the thin ferromagnetic metal film.
Claim 2
Dependent Claim
70 words
A magnetic recording medium comprising a non-magnetic support having provided thereon a thin ferromagnetic metal film, wherein the thin ferromagnetic metal film comprises iron, nitrogen and oxygen atoms within the following atomic percent ranges: 57≦a≦90 2<b<20 5<c<23 b+c<25 in which a, b and c represent the percentage of iron nitrogen and oxygen atoms, respectively, based on the total of iron, nitrogen and oxygen atoms in the thin ferromagnetic metal film.
Claim 3
Dependent Claim
42 words
The magnetic recording medium as in claim 1, wherein the thin ferromagnetic metal film comprises iron, nitrogen and oxygen atoms within the following atomic percent ranges: 65≦a≦85 3<b<15 10<c<22 b+c<25 in which a, b and c are defined as in claim 1.
Claim 4
Dependent Claim
38 words
The magnetic recording medium as in claim 2, wherein the thin ferromagnetic metal film contains about from 8 to 12 atomic % of a nitrogen atom and contains from 10 to 12 atomic % of an oxygen atom.
Claim 5
Dependent Claim
28 words
The magnetic recording medium as in claim 1, wherein the thin ferromagnetic metal film is provided on the non-magnetic support at a thickness of 0.02 to 5.0 μm.
Claim 6
Dependent Claim
28 words
The magnetic recording medium as in claim 1, wherein the thin ferromagnetic metal film is provided on the non-magnetic support at a thickness of 0.05 to 2.0 μm.
Claim 7
Dependent Claim
33 words
The magnetic recording medium as in claim 1, wherein the thin ferromagnetic metal film is formed by depositing vaporized iron atoms on the non-magnetic support with an incident angle which is continuously decreased.
Claim 8
Dependent Claim
24 words
The magnetic recording medium as in claim 1, wherein the thin ferromagnetic metal film consists essentially of iron atoms, nitrogen atoms and oxygen atoms.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-01-31 | 1992-08-01 | 1993-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-31 | 1996-08-01 | 1997-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-31 | 2000-08-01 | 2001-01-31 | $7700.00 | Window Closed / Lapsed |