US4780781A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thin film magnetic head having magnetic film of Co-Ni-Fe alloy
Assignee: HGST Japan Ltd
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Filing: 1985-09-24
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Granted: 1988-10-25
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Expires: 2005-09-24
Abstract
Abstract A thin film magnetic head comprising a lower magnetic film, an upper magnetic film which is formed over the lower magnetic film and in which one end is come into contact with one end of the lower magnetic film and the other end faces the other end of the lower magnetic film through a magnetic gap and thereby forming a magnetic circuit which has a magnetic gap in a part thereof, together with the lower magnetic film, and a conductor coil forming a coil of a predetermined number of turns and passing between the upper and lower magnetic films and crossing the magnetic circuit. Each of the upper and lower magnetic films is formed of a Co-Ni-Fe ternary alloy having a face-centered cubic crystal structure. Also, uniaxial anisotropy is alternately and perpendicularly given in every layer of a predetermined thickness stacked in the direction of thickness of the film.
Inventors
- 👤 Masaaki Sano
- 👤 Katsuya Mitsuoka
- 👤 Makoto Morijiri
- 👤 Shinji Narishige
- 👤 Masanobu Hanazono
- 👤 Toshihiro Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 23:11
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
197 words
A thin film magnetic head comprising: a lower magnetic film; an upper magnetic film which is formed over said lower magnetic film and in which one end is in contact with one end of said lower magnetic film and the other end faces the other end of the lower magnetic film through a magnetic gap, thereby forming a magnetic circuit and a conductor coil forming a coil of a predetermined number of turns and passing between said upper and lower magnetic films, wherein each of said upper and lower magnetic films is formed of a material containing at least 97 weight % of cobalt alloy essentially consisting of cobalt of 62-95 weight %, nickel of 3-30 weight %, and iron of 2-8 weight % and having a face-centered cubic crystal structure, and each of said upper and lower magnetic films has uniaxial anisotropy that alternates in substantially perpendicular directions throughout the thickness of each of said upper and lower magnetic films, said uniaxial anisotropy being induced into each of said upper and lower magnetic films by periodically applying a magnetic field parallel to a substrate surface over which each of said upper and lower films is formed.
Claim 2
Dependent Claim
197 words
A thin film magnetic head comprising: a lower magnetic film; an upper magnetic film which is formed over said lower magnetic film and in which one end is in contact with one end of said lower magnetic film and the other end faces the other end of the lower magnetic film through a magnetic gap, thereby forming a magnetic circuit and a conductor coil forming a coil of a predetermined number of turns and passing between said upper and lower magnetic films, wherein each of said upper and lower magnetic films is formed of a material containing at least 97 weight % of cobalt alloy essentially consisting of cobalt of 62-95 weight %, nickel of 3-30 weight %, and iron of 2-8 weight % and having a face-centered cubic crystal structure, and each of said upper and lower magnetic films has uniaxial anisotropy that alternates in substantially perpendicular directions throughout the thickness of each of said upper and lower magnetic films, said uniaxial anisotropy being induced into each of said upper and lower magnetic films by periodically applying a magnetic field parallel to a substrate surface over which each of said upper and lower films is formed.
Claim 3
Dependent Claim
51 words
A thin film magnetic head according to claim 1, wherein a magneto-striction coefficient of each of said upper and lower magnetic films lies within a range of +2×10 -6 to -2×10 -6 , an anisotropic magnetic field is below 10 oersteds and a saturation magnetic flux density is over 1.3 teslas.
Claim 4
Dependent Claim
39 words
A thin film magnetic head according to claim 1, wherein the composition ratio of said cobalt alloy is essentially 12-22 weight % Ni, 2-8 weight % Fe, and the residual composition of Co of at least 72 weight %.
Claim 5
Dependent Claim
32 words
A thin film magnetic head according to claim 1, wherein said material further includes 0.05-3 weight % of at least one element selected from the group consisting of In, Sb, and Bi.
Claim 6
Dependent Claim
74 words
A thin film magnetic head according to claim 1, wherein each of said upper and lower magnetic films is obtained by applying magnetic fields in parallel to a substrate surface over which each of said upper and lower magnetic films is formed, said magnetic fields being alternately and sequentially applied in a first direction and a second direction substantially orthogonal to said first direction while depositing each of said upper and lower magnetic films.
Claim 7
Dependent Claim
22 words
A thin film magnetic head according to claim 1, wherein each of said upper and lower magnetic films is formed by plating.
Claim 8
Dependent Claim
19 words
A thin film magnetic head according to claim 1, wherein said material further includes B of 0.05-0.5 weight %.
Claim 9
Dependent Claim
40 words
A thin film magnetic head according to claim 1, wherein at least one of said upper magnetic film and said lower magnetic film includes Co of 62-95 weight %, Ni of 3-30 weight %, and Fe of 2-8 weight %.
Claim 10
Dependent Claim
45 words
A thin film magnetic head according to claim 1, wherein at least one of said upper magnetic film and said lower magnetic film includes Ni of 12-22 weight %, Fe of 2-8 weight %, and the residual composition including at least 72 weight % Co.
Claim 11
Dependent Claim
51 words
A thin film magnetic head according to claim 1, wherein at least one of said upper magnetic film and said lower magnetic film includes Ni of 12-22 weight %, Fe of 2-8 weight %, B of 0.05-0.5 weight %, and the residual composition of Co of at least 72 weight %.
Claim 12
Dependent Claim
30 words
A thin film magnetic head according to claim 1, wherein each of said upper and lower magnetic films exhibits an anisotropic magnetic field less than or equal to 10 oersteds.
Claim 13
Dependent Claim
35 words
A thin film magnetic head according to claim 11, wherein each of said upper and lower magnetic films has uniaxial anisotropy parallel to a major surface of each of said upper and lower magnetic films.
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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) | 1991-10-25 | 1992-04-25 | 1992-10-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-25 | 1996-04-25 | 1996-10-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-25 | 2000-04-25 | 2000-10-25 | $7700.00 | Window Closed / Lapsed |