US4868698A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic head
Assignee: Panasonic Holdings Corp
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Filing: 1988-03-02
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Granted: 1989-09-19
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Expires: 2008-03-02
Abstract
Abstract A magnetic head having a recording capacity for sufficiently deriving performance of a high coercive magnetic tape and capable of recording and reproducing signals of very high frequencies at high efficiency. The magnetic head of the present invention includes ferromagnetic thin films and insulative thin films alternately laminated one upon another to form a multi-layered film magnetic core which constitutes part or all of a magnetic path, with the ferromagnetic thin films being so arranged that the directions of their anisotropy are different from each other, and thus, Snoek's limit, due to ferromagnetic resonance, is broken through, thus, making it possible to record and reproduce signals in an efficient manner up to high frequency band regions.
Inventors
- 👤 Ken Takahashi
- 👤 Hiroshi Yohda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:35
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; G11B5/3109; G11B5/313; G11B5/147; G11B5/3143; G11B5/3146; G11B5/3153
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
79 words
A magnetic head, including: a multi-layered magnetic core, said core comprising; a plurality of ferromagnetic thin films having uniaxial anisotropy within the plane of each film; and a plurality of insulating thin films; said ferromagnetic films and said insulating films alternately disposed in a laminated stack, and the direction of anisotropy of alternate ones of said ferromagnetic films in said stack arranged generally perpendicular to the direction of anisotropy of remaining ones of said ferromagnetic films in said stack.
Claim 2
Dependent Claim
79 words
A magnetic head, including: a multi-layered magnetic core, said core comprising; a plurality of ferromagnetic thin films having uniaxial anisotropy within the plane of each film; and a plurality of insulating thin films; said ferromagnetic films and said insulating films alternately disposed in a laminated stack, and the direction of anisotropy of alternate ones of said ferromagnetic films in said stack arranged generally perpendicular to the direction of anisotropy of remaining ones of said ferromagnetic films in said stack.
Claim 3
Dependent Claim
19 words
A magnetic head as in claim 1, wherein said ferromagnetic thin films are formed of an amorphous magnetic alloy.
Claim 4
Dependent Claim
17 words
A magnetic head as in claim 1, wherein said ferromagnetic thin films are formed of sendust alloy.
Claim 5
Dependent Claim
18 words
A magnetic head as in claim 1, wherein said insulating thin films are formed of SiO 2 .
Claim 6
Dependent Claim
130 words
A magnetic head, including: a multi-layered magnetic core, said core comprising; a plurality of ferromagnetic thin films having uniaxial anisotropy within the plane of each film; and a plurality of insulating thin films; said ferromagnetic films and said insulating films alternately disposed in a laminated stack, the direction of anisotropy of alternate ones of said ferromagnetic films in said stack arranged generally perpendicular to the direction of anisotropy of remaining ones of said ferromagnetic films in said stack, the easy axis of magnetization of said alternate ones of said ferromagnetic films arranged to be generally normal to a sliding surface of a recording medium, and the combined thickness of said alternate ones of said ferromagnetic films is greater than the combined thickness of said remaining ones of said ferromagnetic films.
Claim 7
Dependent Claim
130 words
A magnetic head, including: a multi-layered magnetic core, said core comprising; a plurality of ferromagnetic thin films having uniaxial anisotropy within the plane of each film; and a plurality of insulating thin films; said ferromagnetic films and said insulating films alternately disposed in a laminated stack, the direction of anisotropy of alternate ones of said ferromagnetic films in said stack arranged generally perpendicular to the direction of anisotropy of remaining ones of said ferromagnetic films in said stack, the easy axis of magnetization of said alternate ones of said ferromagnetic films arranged to be generally normal to a sliding surface of a recording medium, and the combined thickness of said alternate ones of said ferromagnetic films is greater than the combined thickness of said remaining ones of said ferromagnetic films.
Claim 8
Dependent Claim
35 words
A magnetic head as in claim 5, wherein the thickness of each of said alternate ones of said ferromagnetic films is greater than the thickness of each of said remaining ones of said ferromagnetic films.
Claim 9
Dependent Claim
38 words
A magnetic head as in claim 6, wherein the thickness of each of said alternate ones of said ferromagnetic films is approximately three times greater than the thickness of each of said remaining ones of said ferromagnetic films.
Claim 10
Dependent Claim
19 words
A magnetic head as in claim 5, wherein said ferromagnetic thin films are formed of an amorphous magnetic alloy.
Claim 11
Dependent Claim
17 words
A magnetic head as in claim 5, wherein said ferromagnetic thin films are formed of sendust alloy.
Claim 12
Dependent Claim
18 words
A magnetic head as in claim 5, wherein said insulating thin films are formed of SiO 2 .
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |