US4631202A
Expired / Lapsed
US
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Thin film magnetic recording film
Assignee: HP Inc
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Filing: 1986-04-21
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Granted: 1986-12-23
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Expires: 2006-04-21
Abstract
Abstract A thin film magnetic recording disc is provided wherein the magnetic layer is an alloy of cobalt and platinum disposed on a chromium layer. A barrier layer of chromium is formed on the cobalt-platinum film and a wear layer of an oxide of cobalt is provided on the barrier layer. The platinum content in the magnetic film is varied so as to provide a magnetic film with a desired coercivity which is significantly less dependent upon film thickness. This permits the cobalt-platinum film thickness to be adjusted to meet a wide range of recording system design parameters. The coercivity of the magnetic film may be determined primarily by the amount of platinum in the alloy and the saturation magnetization-thickness product of the film is determined primarily by the film thickness.
Inventors
- 👤 James E. Opfer
- 👤 Bangalore R. Natarajan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 07:09
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/7368; G11B5/7373; G11B5/739; G11B5/73911; G11B5/73913; G11B5/73917; G11B5/73919
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
86 words
A method of providing a film of an alloy of cobalt and platinum having certain magnetic properties comprising: (a) forming a layer of chromium on a substrate; (b) depositing said film of said alloy of cobalt and platinum on said layer of chromium; (c) forming said film to a predetermined thickness to obtain a predetermined magnetization-thickness product thereof; and (d) setting the percentage of platinum of said alloy to obtain a predetermined coercivity, said percentage of platinum ranging from about 1 to about 20 atomic percent.
Claim 2
Independent Claim
86 words
A method of providing a film of an alloy of cobalt and platinum having certain magnetic properties comprising: (a) forming a layer of chromium on a substrate; (b) depositing said film of said alloy of cobalt and platinum on said layer of chromium; (c) forming said film to a predetermined thickness to obtain a predetermined magnetization-thickness product thereof; and (d) setting the percentage of platinum of said alloy to obtain a predetermined coercivity, said percentage of platinum ranging from about 1 to about 20 atomic percent.
Claim 3
Dependent Claim
20 words
The method of claim 1 wherein said chromium layer is formed to a predetermined thickness to further adjust said coercivity.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein a barrier layer is disposed on said magnetic layer.
Claim 5
Dependent Claim
23 words
The method of claim 3 wherein said barrier layer is a material selected from the group consisting of chromium, titanium, tantalum and zirconium.
Claim 6
Dependent Claim
11 words
The method of claim 4 wherein said barrier layer is chromium.
Claim 7
Dependent Claim
18 words
The method of claim 1 wherein said magnetic layer contains from about 1.5 to 7 atomic percent platinum.
Claim 8
Dependent Claim
15 words
The method of claim 6 wherein said magnetic layer contains about 3 atomic percent platinum.
Claim 9
Dependent Claim
15 words
The method of claim 1 wherein a wear layer is disposed on said barrier layer.
Claim 10
Dependent Claim
26 words
The method of claim 8 wherein said wear layer is a material selected from the group consisting of the oxides of cobalt, titanium, silicon and aluminum.
Claim 11
Dependent Claim
12 words
The method of claim 9 wherein said wear layer is cobalt oxide.
Claim 12
Independent Claim
95 words
A method of providing a magnetic film of an alloy of cobalt and platinum supported on a substrate and having a predetermined coercivity and predetermined magnetization-thickness product obtained by: (a) forming a layer of chromium or said substrate to a predetermined thickness to provide a secondary adjustment of said coercivity; and (b) depositing said magnetic film of said alloy of cobalt and platinum on said layer of chromium to a predetermined thickness to provide said predetermined magnetization-thickness product, said alloy formed containing predetermined amount of said platinum to provide a primary adjustment of said coercivity.
Claim 13
Independent Claim
95 words
A method of providing a magnetic film of an alloy of cobalt and platinum supported on a substrate and having a predetermined coercivity and predetermined magnetization-thickness product obtained by: (a) forming a layer of chromium or said substrate to a predetermined thickness to provide a secondary adjustment of said coercivity; and (b) depositing said magnetic film of said alloy of cobalt and platinum on said layer of chromium to a predetermined thickness to provide said predetermined magnetization-thickness product, said alloy formed containing predetermined amount of said platinum to provide a primary adjustment of said coercivity.
Claim 14
Dependent Claim
21 words
The method of claim 11 wherein said predetermined amount of said platinum ranges from about 1 to about 20 atomic percent.
Claim 15
Dependent Claim
20 words
The method of claim 12 wherein said predetermined amount of said platinum ranges from about 1.5 to 7 atomic percent.
Claim 16
Dependent Claim
17 words
The method of claim 13 wherein said predetermined amount of said platinum is about 3 atomic percent.
Claim 17
Dependent Claim
19 words
The method of claim 11 wherein predetermined thickness of said chromium layer ranges from about 1,000 to 3,000 Å.
Claim 18
Dependent Claim
20 words
The method of claim 11 wherein said predetermined thickness of said magnetic film ranges from about 125 to 1,000 Å.
Claim 19
Independent Claim
147 words
A method of fabricating a magnetic recording disc including a magnetic film supported on a substrate having a predetermined magnetization-thickness factor and a predetermined coercivity comprising: (a) forming a surface layer of an alloy of nickel and phosphorus on a substrate of aluminum; (b) forming a layer of chromium on said surface layer; (c) forming said chromium layer to a predetermined thickness to adjust said coercivity of said magnetic film; (d) depositing said magnetic film comprising an alloy of cobalt and aluminum on said layer of chromium; (e) forming said film to a predetermined thickness to obtain said predetermined magnetization-thickness factor; (f) setting the percentage of platinum of said alloy to obtain said predetermined coercivity, said percentage of platinum ranging from about 1 to about 20 atomic percent; (g) forming a barrier layer on said magnetic film; and (h) forming a wear layer on said barrier layer.
Claim 20
Independent Claim
147 words
A method of fabricating a magnetic recording disc including a magnetic film supported on a substrate having a predetermined magnetization-thickness factor and a predetermined coercivity comprising: (a) forming a surface layer of an alloy of nickel and phosphorus on a substrate of aluminum; (b) forming a layer of chromium on said surface layer; (c) forming said chromium layer to a predetermined thickness to adjust said coercivity of said magnetic film; (d) depositing said magnetic film comprising an alloy of cobalt and aluminum on said layer of chromium; (e) forming said film to a predetermined thickness to obtain said predetermined magnetization-thickness factor; (f) setting the percentage of platinum of said alloy to obtain said predetermined coercivity, said percentage of platinum ranging from about 1 to about 20 atomic percent; (g) forming a barrier layer on said magnetic film; and (h) forming a wear layer on said barrier layer.
Claim 21
Dependent Claim
64 words
The method of claim 17 wherein said layer of chromium is formed to a thickness of at least about 1,000 Å, said magnetic film is formed to a thickness of at least about 125 Å, said barrier layer is formed to a thickness of at least about 100 Å and said wear layer is formed to a thickness of at least about 250 Å.
Claim 22
Dependent Claim
23 words
The method of claim 17 wherein said barrier layer is a material selected from the group consisting of chromium, titanium, tantalum and zirconium.
Claim 23
Dependent Claim
11 words
The method of claim 19 wherein said barrier layer is chromium.
Claim 24
Dependent Claim
26 words
The method of claim 17 wherein said wear layer is a material selected from the group consisting of the oxides of cobalt, titanium, silicon and aluminum.
Claim 25
Dependent Claim
12 words
The method of claim 21 wherein said wear layer is cobalt oxide.
Claim 26
Dependent Claim
18 words
The method of claim 17 wherein said magnetic layer contains from about 1.5 to 7 atomic percent platinum.
Claim 27
Dependent Claim
15 words
The method of claim 23 wherein said magnetic layer contains about 3 atomic percent platinum.
Claim 28
Independent Claim
234 words
A method of fabricating a magnetic recording disc including a magnetic film supported on a substrate of aluminum, said magnetic film having a predetermined magnetization-thickness factor and a predetermined coercivity comprising: (a) forming a surface layer of an alloy of nickel and phosphorus on a substrate of aluminum; (b) forming a layer of chromium on said surface layer; (c) forming said chromium layer to a predetermined thickness ranging from about 1,000 to 3,000 Å to provide a secondary adjustment of said coercivity of said magnetic film; (d) depositing said magnetic film comprising an alloy of cobalt and aluminum on said layer of chromium, said magnetic film being deposited to a thickness ranging from about 125 to 1,000 Å; (e) forming said film to a predetermined thickness to obtain said predetermined magnetization-thickness factor; (f) setting the percentage of platinum of said alloy to provide a primary adjustment of said coercivity, said percentage of platinum ranging from about 1 to about 20 atomic percent; (g) forming a barrier layer ranging in thickness from about 100 to 600 Å on said magnetic film, said barrier layer comprising a material selected from the group consisting of chromium, titanium, tantalum and zirconium; and (h) forming a wear layer at least about 250 Å thick on said barrier layer, said wear layer comprising a protective material selected from the group consisting of the oxides of cobalt, titanium, silicon and aluminum.
Claim 29
Independent Claim
234 words
A method of fabricating a magnetic recording disc including a magnetic film supported on a substrate of aluminum, said magnetic film having a predetermined magnetization-thickness factor and a predetermined coercivity comprising: (a) forming a surface layer of an alloy of nickel and phosphorus on a substrate of aluminum; (b) forming a layer of chromium on said surface layer; (c) forming said chromium layer to a predetermined thickness ranging from about 1,000 to 3,000 Å to provide a secondary adjustment of said coercivity of said magnetic film; (d) depositing said magnetic film comprising an alloy of cobalt and aluminum on said layer of chromium, said magnetic film being deposited to a thickness ranging from about 125 to 1,000 Å; (e) forming said film to a predetermined thickness to obtain said predetermined magnetization-thickness factor; (f) setting the percentage of platinum of said alloy to provide a primary adjustment of said coercivity, said percentage of platinum ranging from about 1 to about 20 atomic percent; (g) forming a barrier layer ranging in thickness from about 100 to 600 Å on said magnetic film, said barrier layer comprising a material selected from the group consisting of chromium, titanium, tantalum and zirconium; and (h) forming a wear layer at least about 250 Å thick on said barrier layer, said wear layer comprising a protective material selected from the group consisting of the oxides of cobalt, titanium, silicon and aluminum.
Claim 30
Dependent Claim
18 words
The method of claim 25 wherein said percentage of platinum ranges from about 1.5 to 7 atomic percent.
Claim 31
Dependent Claim
15 words
The method of claim 26 wherein said percentage of platinum is about 3 atomic percent.
Claim 32
Dependent Claim
43 words
The method of claim 27 wherein said layer of chromium is about 2,200 Å thick, said magnetic film is about 410 Å thick, said barrier layer comprises chromium about 500 Å thick and said wear layer comprises cobalt oxide about 420 Å thick.
Claim 33
Dependent Claim
24 words
The method of claim 26 wherein said substrate member is about 0.075 inches thick and said surface layer thereon is about 0.0003 inches thick.
Claim 34
Independent Claim
107 words
A method of making a magnetic recording disc comprising a substrate member and a magnetic film formed thereon, said method including forming a layer of chromium on said substrate member and depositing a magnetic film on said chromium layer, said magnetic film comprising an alloy of cobalt and platinum containing from about 1 to about 20 atomic percent platinum, said magnetic film being formed to a predetermined thickness to provide a predetermined magnetization-thickness product and having a predetermined concentration of platinum to provide a coercivity in a predetermined range, said layer of chromium being formed to a predetermined thickness to further adjust the value of said coercivity.
Claim 35
Independent Claim
107 words
A method of making a magnetic recording disc comprising a substrate member and a magnetic film formed thereon, said method including forming a layer of chromium on said substrate member and depositing a magnetic film on said chromium layer, said magnetic film comprising an alloy of cobalt and platinum containing from about 1 to about 20 atomic percent platinum, said magnetic film being formed to a predetermined thickness to provide a predetermined magnetization-thickness product and having a predetermined concentration of platinum to provide a coercivity in a predetermined range, said layer of chromium being formed to a predetermined thickness to further adjust the value of said coercivity.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-22 | 1990-06-23 | 1990-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-22 | 1994-06-23 | 1994-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-22 | 1998-06-23 | 1998-12-23 | $7700.00 | Window Closed / Lapsed |