US5051288A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film magnetic recording disk comprising alternating layers of a CoNi or CoPt alloy and a non-magnetic spacer layer
Assignee: HGST Netherlands BV
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Filing: 1989-03-16
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Granted: 1991-09-24
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Expires: 2009-03-16
Abstract
Abstract An improved CoPt based or CoNi based alloy magnetic recording disk for horizontal recording has a magnetic recording layer which is a laminated structure of relatively thin magnetic alloy films separated by relatively thin non-magnetic spacer films. The resulting laminated disk structure has substantially decreased intrinsic media noise at high linear recording densities.
Inventors
- 👤 Richard H. Ahlert
- 👤 James K. Howard
- 👤 Steven E. Lambert
- 👤 Ian L. Sanders
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:08
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/676; G11B5/678; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/923; Y10S428/924; Y10S428/926; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12632; Y10T428/12771; Y10T428/12806
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
65 words
A magnetic recording disk for horizontal recording comprising: a substrate; and a laminated magnetic layer formed over the substrate, the laminated magnetic layer further comprising alternating films of a magnetic film of a cobalt-based alloy having platinum or nickel present in the alloy and a non-magnetic spacer film, the laminated layer having at least two of said magnetic films and one of said spacer films.
Claim 2
Dependent Claim
65 words
A magnetic recording disk for horizontal recording comprising: a substrate; and a laminated magnetic layer formed over the substrate, the laminated magnetic layer further comprising alternating films of a magnetic film of a cobalt-based alloy having platinum or nickel present in the alloy and a non-magnetic spacer film, the laminated layer having at least two of said magnetic films and one of said spacer films.
Claim 3
Dependent Claim
19 words
A disk according to claim 1 further comprising a non-magnetic underlayer between the substrate and the laminated magnetic layer.
Claim 4
Dependent Claim
22 words
A disk according to claim 2 wherein the underlayer is formed of either chromium, molybdenum or an alloy comprising chromium and vanadium.
Claim 5
Dependent Claim
15 words
A disk according to claim 1 wherein the magnetic film alloy includes chromium or molybdenum.
Claim 6
Dependent Claim
23 words
A disk according to claim 1 wherein the non-magnetic spacer film is formed of chromium, molybdenum or an alloy comprising chromium and vanadium.
Claim 7
Dependent Claim
20 words
A disk according to claim 1 wherein each of the spacer films has a thickness less than approximately 80 Angstroms.
Claim 8
Dependent Claim
25 words
A disk according to claim 1 wherein the laminated magnetic layer has a coercivity squareness S * in the range of approximately 0.6 to 0.8.
Claim 9
Dependent Claim
99 words
A magnetic recording disk for horizontal recording comprising: a substrate; and a first magnetic film of an alloy comprising cobalt, chromium and platinum having a thickness less than approximately 250 Angstroms formed over the substrate; a first non-magnetic film of chromium or an alloy comprising chromium and vanadium having a thickness less than approximately 80 Angstroms formed over said first magnetic film; a second magnetic film of an alloy comprising cobalt, chromium and platinum having a thickness of less than approximately 250 Angstroms formed over said first non-magnetic film; and a protective overcoat formed over said second magnetic film.
Claim 10
Dependent Claim
99 words
A magnetic recording disk for horizontal recording comprising: a substrate; and a first magnetic film of an alloy comprising cobalt, chromium and platinum having a thickness less than approximately 250 Angstroms formed over the substrate; a first non-magnetic film of chromium or an alloy comprising chromium and vanadium having a thickness less than approximately 80 Angstroms formed over said first magnetic film; a second magnetic film of an alloy comprising cobalt, chromium and platinum having a thickness of less than approximately 250 Angstroms formed over said first non-magnetic film; and a protective overcoat formed over said second magnetic film.
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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) | 1994-09-23 | 1995-03-25 | 1995-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-23 | 1999-03-25 | 1999-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-23 | 2003-03-25 | 2003-09-24 | $7700.00 | Window Closed / Lapsed |