US4540638A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-magnetic substrate material
Assignee: Hitachi Ltd
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Filing: 1984-03-20
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Granted: 1985-09-10
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Expires: 2004-03-20
Abstract
Abstract A thin film magnetic material assembly for a magnetic head which has a non-magnetic substrate material and a magnetic metallic film vapor deposited thereon. The substrate material has a thermal coefficient of expansion approximating that of the magnetic metallic film. The substrate has a NaCl lattice structure and a composition represented by the formula NixMn2-xO2 where 0.25</=x<1. The substrate can optionally contain not more than 10% by weight of at least one of the group Al, Cr, Si, Sn, Ba as a secondary component. The magnetic metallic film most suitable in connection with the present invention is Fe-Ni, Fe-Al-Si or similar based alloys.
Inventors
- 👤 Masahiko Sakakihara
- 👤 Kenzi Hasegawa
- 👤 Akira Iwama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:23
CPC Classifications
H; H01; H01F; H01F10/00; H01F10/26; H01F10/28; G; G11; G11B; G11B5/00; G11B5/62; G11B5/73; G11B5/739; G11B5/73911; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/11; Y10T428/1157
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
98 words
A thin film magnetic assembly for a magnetic head, said assembly comprising a non-magnetic substrate material and a magnetic metallic film vapor-deposited on the substrate material, wherein the substrate material has a thermal expansion coefficient approximating that of the magnetic metallic film, a NaCl-type lattice structure and a nickel-manganese oxide composition represented by the formula: Ni.sub.x Mn.sub.2-x O.sub.2 wherein 0.05≦x<1, said composition optionally containing not more than 10% by weight of at least one individual element of the group consisting of Al, Cr, Si, Sn and Ba as a secondary component on the basis of said nickel-maganese oxide.
Claim 2
Dependent Claim
98 words
A thin film magnetic assembly for a magnetic head, said assembly comprising a non-magnetic substrate material and a magnetic metallic film vapor-deposited on the substrate material, wherein the substrate material has a thermal expansion coefficient approximating that of the magnetic metallic film, a NaCl-type lattice structure and a nickel-manganese oxide composition represented by the formula: Ni.sub.x Mn.sub.2-x O.sub.2 wherein 0.05≦x<1, said composition optionally containing not more than 10% by weight of at least one individual element of the group consisting of Al, Cr, Si, Sn and Ba as a secondary component on the basis of said nickel-maganese oxide.
Claim 3
Dependent Claim
17 words
The thin film magnetic assembly as set forth in claim 1, wherein the secondary component comprises Al.
Claim 4
Dependent Claim
19 words
The thin film magnetic assembly of claim 1, wherein the secondary component is an oxide of the individual elements.
Claim 5
Dependent Claim
17 words
The thin film magnetic assembly of claim 3, wherein the oxide is Al 2 O 3 .
Claim 6
Dependent Claim
21 words
The thin film magnetic assembly of claim 1, wherein the substrate material has a thermal expansion coefficient of 120-150×10 -7 /°C.
Claim 7
Dependent Claim
23 words
The thin film magnetic assembly of claim 5, wherein the magnetic metallic film comprises an Fe-Ni based alloy or an Fe-Al-Si based alloy.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-09 | 1989-03-11 | 1989-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-09 | 1993-03-11 | 1993-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-09 | 1997-03-11 | 1997-09-10 | $7700.00 | Window Closed / Lapsed |