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EP0205239A2
Expired / Lapsed
EP
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Thin film magnetic disc
Assignee: Akashic Memories Corp
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Filing: 1986-04-17
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Granted: —
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Expires: 2006-04-17
Abstract
Abstract @ A new high quality, low cost, thin-film magnetic recording member is provided, which has a coercive field strength greater than 650 Oe, a saturation magnetization greater than 10,000 Gauss, and a squareness ratio of 0.9 or larger. The member includes a substrate on which is directly sputter deposited a chromium layer, without the use of an intervening nickel-containing layer between the substrate and the chromium. A nickel-cobalt recording layer is then sputter deposited directly onto the chromium layer. In the preferred mode, the start of that nickel-cobalt deposition begins less than 100 seconds after the chromium deposition is terminated and is followed by the sputtering of a protective layer. Before the chromium deposition, the substrate is preheated to drive off adsorbed gases, and to establish the proper conditions forthe chromium deposition. The substrate is also heated during the time between when the chromium deposition ends and the nickel-cobalt deposition begins.
Inventors
- 👤 John C. Scott
- 👤 Eric K. Li
- 👤 Hudson A. Washburn
- 👤 Nal T. Viswanathan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 06:39
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/84; G11B5/851
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
53 words
A magnetic recording element comprising: a substrate having at least one supporting surface, said supporting surface not having a nickel-containing layer thereon; a chromium layer sputter-deposited directly onto said supporting surface; a nickel-cobalt magnetic recording layer sputter-deposited directly onto said chromium layer; and a protective layer deposited onto said nickel-cobalt magnetic recording layer.
Claim 2
Dependent Claim
53 words
A magnetic recording element comprising: a substrate having at least one supporting surface, said supporting surface not having a nickel-containing layer thereon; a chromium layer sputter-deposited directly onto said supporting surface; a nickel-cobalt magnetic recording layer sputter-deposited directly onto said chromium layer; and a protective layer deposited onto said nickel-cobalt magnetic recording layer.
Claim 3
Dependent Claim
20 words
A recording element as in claim 1, wherein said chromium layer comprises at least 99.5% by weight of pure chromium.
Claim 4
Dependent Claim
21 words
A recording element as in claim 2 wherein said nickel-cobalt layer comprises at least 99.9% by weight of nickel and cobalt.
Claim 5
Dependent Claim
23 words
A recording element as in claim 1 wherein said nickel-cobalt layer comprises at least 15% and at most 23% by weight of nickel.
Claim 6
Dependent Claim
25 words
A recording element as in claim 4 wherein said chromium layer is a minimum of 1000 A thick and a maximum of 4500 A thick.
Claim 7
Dependent Claim
19 words
A recording element as in claim 5 wherein said chromium layer has a thickness of 2000 A + 20%.
Claim 8
Dependent Claim
23 words
A recording element as in claim 5 wherein said nickel-cobalt layer is a minimum of 350 A and a maximum of 1000 A.
Claim 9
Dependent Claim
16 words
A recording element as in claim 7 wherein said nickel-cobalt layer is 400 A + 10%.
Claim 10
Independent Claim
98 words
A method of constructing a thin-film disk recording device comprising: heating a substrate to a temperature in the range of 190°C to 350°C, said substrate having a surface which does not have a nickel-containing layer thereon; sputtering chromium directly onto said surface during a first preselected time to form a chromium layer on said substrate; sputtering a nickel-cobalt magnetic layer onto said chromium layer during a second preselected time; heating said substrate and chromium layer thereon during the time between said first preselected time and said second preselected time; and depositing a protective layer over said nickel-cobalt layer.
Claim 11
Independent Claim
98 words
A method of constructing a thin-film disk recording device comprising: heating a substrate to a temperature in the range of 190°C to 350°C, said substrate having a surface which does not have a nickel-containing layer thereon; sputtering chromium directly onto said surface during a first preselected time to form a chromium layer on said substrate; sputtering a nickel-cobalt magnetic layer onto said chromium layer during a second preselected time; heating said substrate and chromium layer thereon during the time between said first preselected time and said second preselected time; and depositing a protective layer over said nickel-cobalt layer.
Claim 12
Dependent Claim
37 words
A method as in claim 9 wherein the step of heating during the time between said first preselected time and said second preselected time comprises placing said substrate with said chromium layer thereon on a heated pedestal.
Claim 13
Dependent Claim
21 words
ll. A method as in claim 10 wherein said heated pedestal has a temperature in the range of 190°C to 350°C.
Claim 14
Dependent Claim
17 words
A method as in claim 11 wherein the temperature of said pedestal is between 200°C and 330°C.
Claim 15
Dependent Claim
19 words
A method as in claim 12 wherein said chromium layer consists of at least 99.5% by weight of chromium.
Claim 16
Dependent Claim
21 words
A method as in claim 13 wherein said nickel-cobalt layer consists of at least 99.9% by weight of nickel and cobalt.
Claim 17
Dependent Claim
24 words
A method as in claim 11 wherein the time between said first preselected time and said second preselected time is less than 50 minutes.
Claim 18
Dependent Claim
24 words
A method as in claim 15 wherein said time between said first preselected time and said second preselected time is less than 100 seconds.
Claim 19
Dependent Claim
22 words
A method as in claim 9 wherein said sputtering steps are carried out in a vacuum of at least 5x10 -7 Torr.
Claim 20
Dependent Claim
21 words
A method as in claim 17 wherein said heating steps and said sputtering steps are carried out without breaking said vacuum.
Claim 21
Dependent Claim
15 words
A method as in claim 18 wherein said vacuum is at least 1x10 -7 Torr.
References Cited (Backward Citations)
No citation records indexed.
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