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US4652499A
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Magnetic recording medium with a chromium alloy underlayer and a cobalt-based magnetic layer
Assignee: HGST Netherlands BV
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Filing: 1986-04-29
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Granted: 1987-03-24
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Expires: 2006-04-29
Abstract
Abstract An improved cobalt-platinum (CoPt) thin film metal alloy media for horizontal magnetic recording has a squareness greater than prior CoPt thin film metal alloy media. An underlayer of a body-centered-cubic (BCC) chromium-based alloy with a lattice cell constant greater than chromium (Cr), such as chromium-vanadium (CrV), is formed between the substate and the CoPt magnetic layer. The underlayer also improves the magnetic properties of the media when the magnetic layer is an alloy of cobalt-platinum-chromium (CoPtCr).
Inventors
- 👤 James K. Howard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:32
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/656; G11B5/73; G11B5/7368; G11B5/7373; G11B5/739; G11B5/73911; G11B5/73913; G11B5/73917; G11B5/73919; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535; Y10T428/12597; Y10T428/12625; Y10T428/12674; Y10T428/12736; Y10T428/12743; Y10T428/1275; Y10T428/12771; Y10T428/12806; Y10T428/12826; Y10T428/12847; Y10T428/12854; Y10T428/12861; Y10T428/12937; Y10T428/12944
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
43 words
A magnetic recording medium for horizontal recording comprising: a substrate; a nonmagnetic layer formed on the substrate from an alloy of chromium and either vanadium or iron; and a magnetic layer of an alloy comprising cobalt and platinum formed on the nonmagnetic layer.
Claim 2
Dependent Claim
43 words
A magnetic recording medium for horizontal recording comprising: a substrate; a nonmagnetic layer formed on the substrate from an alloy of chromium and either vanadium or iron; and a magnetic layer of an alloy comprising cobalt and platinum formed on the nonmagnetic layer.
Claim 3
Dependent Claim
18 words
The magnetic recording medium according to claim 1 wherein the alloy of the magnetic layer further comprises chromium.
Claim 4
Dependent Claim
13 words
The magnetic recording medium according to claim 1 wherein the substrate is silicon.
Claim 5
Dependent Claim
22 words
The magnetic recording medium according to claim 1 wherein the substrate comprises an aluminum alloy disk having a nickel-phosphorus film formed thereon.
Claim 6
Dependent Claim
18 words
The magnetic recording medium according to claim 1 further comprising a protective overcoat formed over the magnetic layer.
Claim 7
Dependent Claim
23 words
The magnetic recording medium according to claim 1 wherein the underlayer is a chromium-vanadium film having a thickness greater than approximately 200 Angstroms.
Claim 8
Dependent Claim
48 words
A magnetic recording medium for horizontal recording comprising: a substrate; a layer of chromium-vanadium alloy formed on the substrate; and a magnetic layer of an alloy comprising cobalt and platinum formed on the chromium-vanadium alloy layer, the magnetic layer comprising a mixed phase of HCP and FCC crystallites.
Claim 9
Dependent Claim
48 words
A magnetic recording medium for horizontal recording comprising: a substrate; a layer of chromium-vanadium alloy formed on the substrate; and a magnetic layer of an alloy comprising cobalt and platinum formed on the chromium-vanadium alloy layer, the magnetic layer comprising a mixed phase of HCP and FCC crystallites.
References Cited (Backward Citations)
US3321328A
Cited
JPS57198568A
Cited
JPS57205821A
Cited
US4438066A
Cited
EP0140513A1
Cited
EP0145157A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-03-23 | 1990-09-22 | 1991-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-23 | 1994-09-22 | 1995-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-23 | 1998-09-22 | 1999-03-24 | $7700.00 | Window Closed / Lapsed |