US4609593A
Expired / Lapsed
US
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Magnetic recording medium
Assignee: Alps Alpine Co Ltd
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Filing: 1984-07-16
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Granted: 1986-09-02
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Expires: 2004-07-16
Abstract
Abstract A perpendicular magnetic recording medium composed of a base material, a 1st magnetic thin layer formed on the base material, and a perpendicularly magnetizable 2nd magnetic thin layer formed on the 1st magnetic thin layer, wherein the 1st magnetic thin layer is composed of a Co-base ternary amorphous alloy containing small amounts of Hf and Ta.
Inventors
- 👤 Keishi Nakashima
- 👤 Takashi Hatanai
- 👤 Koichi Mukasa
- 👤 Yutaka Shimada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:22
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/672; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465; Y10T428/12493; Y10T428/12535; Y10T428/12556; Y10T428/12562; Y10T428/12569; Y10T428/12597; Y10T428/12771; Y10T428/12806; Y10T428/12826; Y10T428/12847; Y10T428/12854; Y10T428/12861; Y10T428/12931
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
109 words
A magnetic recording medium comprising a base material, a 1st magnetic thin layer formed on the surface of the base material, and a 2nd magnetic thin layer formed on the surface of the 1st magnetic layer and having a perpendicular anisotropy, said 2nd magnetic thin layer being capable of recording data by magnetization in the thickness direction thereof, wherein said 1st magnetic thin layer is composed of a cobalt-based ternary amorphous alloy containing hafnium and tantalum where the content of said hafnium is in the range of from 1 atom% to 5 atom% and the content of said tantalum is in the range of 4 atom% to 10 atom%.
Claim 2
Dependent Claim
109 words
A magnetic recording medium comprising a base material, a 1st magnetic thin layer formed on the surface of the base material, and a 2nd magnetic thin layer formed on the surface of the 1st magnetic layer and having a perpendicular anisotropy, said 2nd magnetic thin layer being capable of recording data by magnetization in the thickness direction thereof, wherein said 1st magnetic thin layer is composed of a cobalt-based ternary amorphous alloy containing hafnium and tantalum where the content of said hafnium is in the range of from 1 atom% to 5 atom% and the content of said tantalum is in the range of 4 atom% to 10 atom%.
Claim 3
Dependent Claim
22 words
The magnetic recording medium as claimed in claim 1, wherein said 2nd magnetic thin layer is composed of a cobalt-chromium system alloy.
Claim 4
Dependent Claim
22 words
A magnetic recording medium according to claim 1 wherein said content of hafnium is in the range 1.5 atom% to 3 atom%.
Claim 5
Dependent Claim
16 words
A magnetic recording medium according to claim 3 wherein said content of tantalum is 4.5 atom%.
Claim 6
Dependent Claim
22 words
A magnetic recording medium according to claim 1 wherein said content of tantalum is in the range 6 atom% to 8 atom%.
Claim 7
Dependent Claim
17 words
A magnetic recording medium according to claim 5 wherein the content of said hafnium is 2.2 atom%.
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) | 1989-09-01 | 1990-03-03 | 1990-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-01 | 1994-03-03 | 1994-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-01 | 1998-03-03 | 1998-09-02 | $7700.00 | Window Closed / Lapsed |