US4622273A
Expired / Lapsed
US
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Recording medium for perpendicular magnetization
Assignee: Alps Alpine Co Ltd
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Filing: 1984-11-05
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Granted: 1986-11-11
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Expires: 2004-11-05
Abstract
Abstract A magnetic recording medium for perpendicular magnetization includes a base of a nonmagnetic material, a first magnetic layer of a soft magnetic material on a surface of the base, a second magnetic layer having perpendicular anisotropy on a surface of the first magnetic layer, the second magnetic layer being magnetized in a transverse direction thereof. The second magnetic layer is composed of a three-element alloy of cobalt, chromium, and hafnium, cobalt being a main component with chromium and hafnium added thereto.
Inventors
- 👤 Keishi Nakashima
- 👤 Takashi Hatanai
- 👤 Koichi Mukasa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:34
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/656; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12736; Y10T428/12743; Y10T428/12771; Y10T428/12861
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
106 words
A magnetic recording medium for perpendicular magnetization, comprising: (a) a base of a non-magnetic material; (b) a first magnetic layer of a soft magnetic material on a surface of said base; (c) a second magnetic layer having perpendicular anisotropy on a surface of said first magnetic layer said second magnetic layer being magnetized in a transverse direction thereof; and (d) said second magnetic layer being composed of a three-element alloy of cobalt, chromium, and hafnium, cobalt being a main component with chromium a minor component and hafnium in the range of about 0.1 to 1.1 atomic % (equivalent to 0.3 to 3.3 wt. %) added thereto.
Claim 2
Dependent Claim
106 words
A magnetic recording medium for perpendicular magnetization, comprising: (a) a base of a non-magnetic material; (b) a first magnetic layer of a soft magnetic material on a surface of said base; (c) a second magnetic layer having perpendicular anisotropy on a surface of said first magnetic layer said second magnetic layer being magnetized in a transverse direction thereof; and (d) said second magnetic layer being composed of a three-element alloy of cobalt, chromium, and hafnium, cobalt being a main component with chromium a minor component and hafnium in the range of about 0.1 to 1.1 atomic % (equivalent to 0.3 to 3.3 wt. %) added thereto.
Claim 3
Dependent Claim
38 words
A magnetic recording medium according to claim 1, wherein said alloy has the composition of (Co 77 .9 Cr 22 .1) 100-x Hf x with a value of x in the range of 0.1 to 1.1 wt. %.
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) | 1989-11-10 | 1990-05-12 | 1990-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-10 | 1994-05-12 | 1994-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-10 | 1998-05-12 | 1998-11-11 | $7700.00 | Window Closed / Lapsed |