Patent US4701374A successfully refreshed from Google Patents.
US4701374A
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Magnetic recording medium
Assignee: Toshiba Corp
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Filing: 1985-07-01
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Granted: 1987-10-20
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Expires: 2005-07-01
Abstract
Abstract A magnetic recording medium obtained by forming a Si-N-O system film on a magnetic recording layer with perpendicular axis of easy magnetization. The magnetic recording layer is a metallic magnetic film such as Co-Cr system alloy film. The oxygen content in the Si-N-O system film is selected preferably to show a maximum absorption of infrared radiation in the range above 830 cm -1 and below 1100 cm -1 of 1/λ (λ is the wavelength of the infrared radiation). Through formation of the Si-N-O system film, the magnetic recording medium can satisfy simultaneously both of the durability and the perpendicular magnetic recording characteristics.
Inventors
- 👤 Masayuki Sagoi
- 👤 Yoichiro Tanaka
- 👤 Hiroki Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:22
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/672; G11B5/72; G11B5/725; G11B5/7253; G11B5/726; G11B5/7262; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
83 words
A magnetic recording medium comprising: a substrate; at least one magnetic layer having an axis of easy magnetization in a direction perpendicular to a surface thereof, formed on the substrate; and a film consisting essentially of silicon, nitrogen, and oxygen, formed on the magnetic layer, the amount of oxygen being selected so as to cause an absorption maximum of infrared radiation in the range of 830 cm -1 to 1100 cm -1 of 1/λ where λ is the wavlength of the infrared radiation.
Claim 2
Dependent Claim
83 words
A magnetic recording medium comprising: a substrate; at least one magnetic layer having an axis of easy magnetization in a direction perpendicular to a surface thereof, formed on the substrate; and a film consisting essentially of silicon, nitrogen, and oxygen, formed on the magnetic layer, the amount of oxygen being selected so as to cause an absorption maximum of infrared radiation in the range of 830 cm -1 to 1100 cm -1 of 1/λ where λ is the wavlength of the infrared radiation.
Claim 3
Dependent Claim
38 words
A magnetic recording medium according to claim 1 wherein said film contains oxygen in an amount to cause an absorption maximum of infrared radition in the range of 850 cm -1 and to 1050 cm -1 of 1/λ.
Claim 4
Dependent Claim
13 words
A magnetic recording medium according to claim 1 wherein said film is amorphous.
Claim 5
Dependent Claim
17 words
A magnetic recording medium according to claim 1 wherein said magnetic layer is a Co-Cr containing alloy.
Claim 6
Dependent Claim
15 words
A magnetic recording medium according to claim 1 wherein said substrate is a flexible disk.
Claim 7
Dependent Claim
23 words
A magnetic recording medium according to claim 1 further including second magnetic and film layers formed on a second surface of said substrate.
Claim 8
Dependent Claim
17 words
A magnetic recording medium according to claim 1 further including a lubricant layer formed on said film.
Claim 9
Dependent Claim
17 words
A magnetic recording medium according to claim 7 wherein said lubricant layer comprises a fluorocarbon containing lubricant.
Claim 10
Dependent Claim
33 words
A magnetic recording medium according to claim 1 wherein said film contains in respective atomic ratio of 45 to 55% of silicon, 10 to 50% of nitrogen, and 5 to 45% of oxygen.
Claim 11
Dependent Claim
21 words
A magnetic recording medium according to claim 1 wherein the thickness of said film is between 20 Å and 500 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) | 1990-10-19 | 1991-04-20 | 1991-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-19 | 1995-04-20 | 1995-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-19 | 1999-04-20 | 1999-10-20 | $7700.00 | Window Closed / Lapsed |