US4677032A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vertical magnetic recording media with multilayered magnetic film structure
Assignee: International Business Machines Corp
•
Filing: 1985-09-23
•
Granted: 1987-06-30
•
Expires: 2005-09-23
Abstract
Abstract A thin film metal alloy medium for vertical recording has a magnetic film structure of individual films, each film being made up of a non-magnetic layer and a magnetic layer. In a preferred embodiment of the medium, each of the layers is a cobalt-chromium-tantalum (CoCrTa) alloy, the tantalum concentration being varied in the different layers in order to provide either the non-magnetic or the magnetic properties to the layers. The medium also includes a soft magnetic underlayer film structure between the substrate and the magnetic film structure to provide a magnetic flux return path. Each film in the underlayer film structure comprises a CoCrTa non-magnetic layer and a CoCrTa magnetic layer, each magnetic layer being sufficiently thin such that the underlayer film structure exhibits in-plane magnetization with no perpendicular magnetic anisotropy.
Inventors
- 👤 Clifford J. Robinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:01
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/62; G11B5/64; G11B5/66; G11B5/676; G11B5/678; Y; Y10; Y10S; Y10S428/00; Y10S428/922; Y10S428/9265; Y10S428/928; Y10T; Y10T428/00; Y10T428/12; Y10T428/12431; Y10T428/12438; Y10T428/12465; Y10T428/12493; Y10T428/12535; Y10T428/12556; Y10T428/12569; Y10T428/12597; Y10T428/12625; Y10T428/12674; Y10T428/12736; Y10T428/12743; Y10T428/1275; Y10T428/12771; Y10T428/12861; Y10T428/12931; Y10T428/12937; Y10T428/12944; Y10T428/12951
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
57 words
A perpendicular magnetic recording medium comprising: a substrate; and a magnetic film structure of a multiplicity of films formed on the substrate, each film comprising a layer of non-magnetic material and a layer of a magnetic metal alloy comprising cobalt and chromium formed on the layer of non-magnetic material, the magnetic film structure having perpendicular magnetic anisotropy.
Claim 2
Dependent Claim
57 words
A perpendicular magnetic recording medium comprising: a substrate; and a magnetic film structure of a multiplicity of films formed on the substrate, each film comprising a layer of non-magnetic material and a layer of a magnetic metal alloy comprising cobalt and chromium formed on the layer of non-magnetic material, the magnetic film structure having perpendicular magnetic anisotropy.
Claim 3
Dependent Claim
17 words
The medium according to claim 1 further comprising a protective overcoat formed on the magnetic film structure.
Claim 4
Dependent Claim
28 words
The medium according to claim 1 wherein the magnetic metal alloy comprises cobalt, chromium and an element from the group consisting of tantalum, niobium, tungsten, titanium and vanadium.
Claim 5
Dependent Claim
31 words
The medium according to claim 1 wherein the layer of non-magnetic material and the layer of magnetic metal alloy in each of the films are alloys consisting of the same elements.
Claim 6
Dependent Claim
27 words
The medium according to claim 1 further comprising a soft magnetic underlayer between the substrate and the magnetic film structure for providing a magnetic flux return path.
Claim 7
Dependent Claim
79 words
The medium according to claim 5 wherein the soft magnetic underlayer further comprises an underlayer film structure of a multiplicity of films, each film in the underlayer film structure comprising a layer of non-magnetic material and a layer of a magnetic metal alloy comprising cobalt and chromium formed on the layer of non-magnetic material, each layer of magnetic metal alloy in the underlayer film structure being sufficiently thin such that the underlayer film structure exhibits no perpendicular magnetic anisotropy.
Claim 8
Dependent Claim
34 words
The medium according to claim 6 wherein the magnetic metal alloy in the underlayer film structure comprises cobalt, chromium and an element selected from the group consisting of tantalum, niobium, tungsten, titanium and vanadium.
Claim 9
Dependent Claim
36 words
The medium according to claim 6 wherein the layer of non-magnetic material and the layer of magnetic metal alloy in each of the films in the underlayer film structure are alloys consisting of the same elements.
Claim 10
Dependent Claim
24 words
The medium according to claim 8 wherein the alloys in the magnetic film structure and the underlayer film structure consist of the same elements.
References Cited (Backward Citations)
JPS5694520A
Cited
JPS57179942A
Cited
US4592948A
Cited
US4594296A
Cited
US4548871A
Cited
JPS59139138A
Cited
US4599280A
Cited
EP0140513A1
Cited
DE3440386A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-06-29 | 1990-12-29 | 1991-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-06-29 | 1994-12-29 | 1995-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-06-29 | 1998-12-29 | 1999-06-30 | $7700.00 | Window Closed / Lapsed |