US5344706A
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Magnetic recording medium comprising an underlayer and a cobalt samarium amorphous magnetic layer having a SmCo5 crystalline interface with the underlayer
Assignee: Carnegie Mellon University
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Filing: 1992-11-12
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Granted: 1994-09-06
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Expires: 2012-11-12
Abstract
Abstract The present invention pertains to a thin film media structure for low noise high density longitudinal magnetic recording. The thin film media structure is comprised of a substrate. The thin film media structure is also comprised of an underlayer in contact with the substrate. Additionally, the thin film media structure is comprised of a CoSm or a CoSmQ film in contact with the underlayer such that the underlayer is between the substrate and the CoSm or CoSmQ. In a preferred embodiment, the underlayer is made of Cr or W and there is additionally an overlayer in contact with the CoSm or CoSmQ film, an overcoat in contact with the overlayer and an organic lubricant disposed on the overcoat. The present invention also pertains to a low noise high coercivity media structure for longitudinal magnetic recording. The high coercivity media structure is comprised of a substrate. The high coercivity media structure is also comprised of a multi-magnetic layer comprised of at least two layers of an alloy of Co and Sm, or Co and Sm and Q with an intermediate layer therebetween, and an underlayer in contact with the substrate and between the substrate and one of the CoSm layers.
Inventors
- 👤 David N. Lambeth
- 👤 E. M. T. Velu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:35
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/65; G11B5/656; G11B5/73; G11B5/7368; G11B5/7373; G11B5/7377; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12465; Y10T428/12493; Y10T428/12771; Y10T428/12806; Y10T428/12826; Y10T428/1284; Y10T428/12847; Y10T428/12854; Y10T428/12861; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
94 words
A thin film media structure having an in plane coercivity of at least 1650 oersteds for longitudinal magnetic recording comprising: a substrate; an underlayer in contact with the substrate, the underlayer being comprised of Cr, W or Mo of a predominantly <110> texture; and film comprised of an alloy of Co and Sm forming a fine grain or amorphous magnetic layer disposed on the underlayer and forming a SmCo 5 crystalline interface with the underlayer such that the underlayer is between the substrate and the film, the film being less than 50 nm thick.
Claim 2
Dependent Claim
94 words
A thin film media structure having an in plane coercivity of at least 1650 oersteds for longitudinal magnetic recording comprising: a substrate; an underlayer in contact with the substrate, the underlayer being comprised of Cr, W or Mo of a predominantly <110> texture; and film comprised of an alloy of Co and Sm forming a fine grain or amorphous magnetic layer disposed on the underlayer and forming a SmCo 5 crystalline interface with the underlayer such that the underlayer is between the substrate and the film, the film being less than 50 nm thick.
Claim 3
Dependent Claim
15 words
A media structure as described in claim 1 wherein the underlayer is 10-5000 angstroms thick.
Claim 4
Dependent Claim
22 words
A media structure as described in claim 2 wherein the CoSm alloy film is from 30 to less than 500 angstroms thick.
Claim 5
Dependent Claim
29 words
A media structure as described in claim 1 including an overlayer in contact with the CoSm film such that the CoSm film is between the overlayer and the underlayer.
Claim 6
Dependent Claim
29 words
A media structure as described in claim 4 including an overcoat in contact with the overlayer such that the overlayer is between the overcoat and the CoSm alloy film.
Claim 7
Dependent Claim
24 words
A media structure as described in claim 5 wherein the overlayer is 10-500 angstroms thick and is comprised of Cr, W, Y or Pt.
Claim 8
Dependent Claim
26 words
A media structure as described in claim 6 wherein the overcoat is 10-500 angstroms thick and is comprised of carbon, SiO 2 or ZrO 2 .
Claim 9
Dependent Claim
21 words
A media structure as described in claim 1 wherein the CoSm is of the form Co 1-x Sm x where 0.005≦x≦0.30.
Claim 10
Dependent Claim
113 words
A thin film media structure having an in plane coercivity of at least 1650 oersteds for longitudinal magnetic recording comprising: a substrate; an underlayer in contact with the substrate, the underlayer being comprised of Cr, W or Mo of a predominantly <110> texture; and at least one layer of a film less than 50 nm thick comprised of an alloy of Co, Sm and Q having a fin grain or amorphous structure and forming a SmCo 5 crystalline interface with the underlayer such that the underlayer is between the substrate and CoSmQ film, wherein Q is selected from the group consisting of Ta, Mo, Bi, Zr, B, Ni, Cr, Pt and combinations thereof.
Claim 11
Dependent Claim
113 words
A thin film media structure having an in plane coercivity of at least 1650 oersteds for longitudinal magnetic recording comprising: a substrate; an underlayer in contact with the substrate, the underlayer being comprised of Cr, W or Mo of a predominantly <110> texture; and at least one layer of a film less than 50 nm thick comprised of an alloy of Co, Sm and Q having a fin grain or amorphous structure and forming a SmCo 5 crystalline interface with the underlayer such that the underlayer is between the substrate and CoSmQ film, wherein Q is selected from the group consisting of Ta, Mo, Bi, Zr, B, Ni, Cr, Pt and combinations thereof.
Claim 12
Dependent Claim
45 words
A media structure as described in claim 9 including an overlayer in contact with the CoSmQ film such that the CoSmQ film is between the overlayer and the underlayer and the overlayer is comprised of Cr, W, Y or Pt and is 10-500 angstroms thick.
Claim 13
Dependent Claim
29 words
A media structure as described in claim 10 including an overcoat in contact with the overlayer such that the overlayer is between the overcoat and the CoSmQ alloy film.
Claim 14
Dependent Claim
25 words
A media structure as described in claim 9 wherein the CoSmQ is of the form Co 1-x-y Sm x Q y where 0.005≦x≦0.3 and 0.01≦y≦0.10.
Claim 15
Dependent Claim
18 words
A media structure as described in claim 9 including an overcoat in contact with the CoSmQ alloy film.
Claim 16
Dependent Claim
41 words
A media structure as described in claim 1 wherein there are multi-magnetic layers comprised of at least two said layers of CoSm film with an intermediate layer therebetween, said underlayer disposed between the substrate and one of the CoSm or layers.
Claim 17
Dependent Claim
40 words
A media structure as described in claim 9 wherein there are multi-magnetic layers comprised of at least two said layers of CoSmQ film with an intermediate layer therebetween, said underlayer disposed between the substrate and one of the CoSmQ layers.
Claim 18
Dependent Claim
42 words
A high coercivity media structure as described in claims 14 or 15 including an overlayer in contact with the multi-magnetic layer such that the multi-magnetic layer is between the underlayer and overlayer and the overlayer and intermediate layer are comprised of Cr.
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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) | 1997-09-05 | 1998-03-07 | 1998-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-09-05 | 2002-03-07 | 2002-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-09-05 | 2006-03-07 | 2006-09-06 | $7700.00 | Window Closed / Lapsed |