US4789598A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film medium for horizontal magnetic recording having an improved cobalt-based alloy magnetic layer
Assignee: International Business Machines Corp
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Filing: 1987-01-20
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Granted: 1988-12-06
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Expires: 2007-01-20
Abstract
Abstract An improved thin film metal alloy media for horizontal magnetic recording has a magnetic layer of an alloy comprising cobalt, platinum and chromium, where the chromium concentration in the alloy is greater than 17 at.%. The media exhibits unexpectedly high signal-to-noise ratio (SNR) and minimal time jitter, thereby resulting in a media which is capable for use at high linear recording density. The media also exhibits excellent corrosion resistance because of the chromium present in the alloy, thereby eliminating the need for a barrier layer between the magnetic layer and the protective overcoat.
Inventors
- 👤 James K. Howard
- 👤 Run-Han Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:06
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/656; G11B5/72; G11B5/727; G11B5/73; G11B5/7368; G11B5/7373; G11B5/739; G11B5/73911; G11B5/73913; G11B5/73917; G11B5/73919; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12806; Y10T428/12826; Y10T428/12847; Y10T428/12861; Y10T428/12875; Y10T428/30
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
77 words
A magnetic recording disk for horizontal recording comprising: a substrate of an aluminum alloy having a nickel-phosphorous (NiP) surface film formed thereon; a magnetic layer formed directly on and adhered directly to the NiP film of the substrate and comprising an alloy of cobalt, platinum and chromium with chromium present in the alloy in an amount greater than 17 atomic percent, the magnetic layer having horizontal magnetic anisotropy; and a protective overcoat formed over the magnetic layer.
Claim 2
Dependent Claim
77 words
A magnetic recording disk for horizontal recording comprising: a substrate of an aluminum alloy having a nickel-phosphorous (NiP) surface film formed thereon; a magnetic layer formed directly on and adhered directly to the NiP film of the substrate and comprising an alloy of cobalt, platinum and chromium with chromium present in the alloy in an amount greater than 17 atomic percent, the magnetic layer having horizontal magnetic anisotropy; and a protective overcoat formed over the magnetic layer.
Claim 3
Dependent Claim
19 words
The magnetic recording disk according to claim 1 wherein the protective overcoat is a sputter-deposited essentially amorphous carbon film.
Claim 4
Dependent Claim
82 words
A magnetic recording disk for horizontal recording comprising: a substrate of either silicon or an aluminum alloy with a nickel-phosphorous surface film; an underlayer consisting of chromium, the underlayer being formed on and adhered to the substrate; a magnetic layer of cobalt-platinum-chromium alloy, with chromium present in the magnetic layer alloy in an amount greater than 17 atomic percent, formed on and adhered to the underlayer, the magnetic layer having horizontal magnetic anisotropy; and a protective overcoat formed over the magnetic layer.
Claim 5
Dependent Claim
82 words
A magnetic recording disk for horizontal recording comprising: a substrate of either silicon or an aluminum alloy with a nickel-phosphorous surface film; an underlayer consisting of chromium, the underlayer being formed on and adhered to the substrate; a magnetic layer of cobalt-platinum-chromium alloy, with chromium present in the magnetic layer alloy in an amount greater than 17 atomic percent, formed on and adhered to the underlayer, the magnetic layer having horizontal magnetic anisotropy; and a protective overcoat formed over the magnetic layer.
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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) | 1991-12-06 | 1992-06-06 | 1992-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-06 | 1996-06-06 | 1996-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-06 | 2000-06-06 | 2000-12-06 | $7700.00 | Window Closed / Lapsed |