US4660113A
Expired / Lapsed
US
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Magnetoresistive thin film head
Assignee: Panasonic Holdings Corp
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Filing: 1982-12-09
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Granted: 1987-04-21
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Expires: 2002-12-09
Abstract
Abstract A magnetoresistive type thin film magnetic head is completely unaffected by external noise and produces only low interference with a recording medium. A magnetoresistive element which constitutes the thin film magnetic head has three terminals constituted by two end terminals and an intermediate terminal. Constant currents which flow in opposite directions are respectively supplied to the two end terminals. A magnetic field of a signal recorded on and reproduced from a single track of the recording medium is applied to the magnetoresistive element, and reproduction outputs of opposite phases appear at the two end terminals. These outputs are differentially amplified by a differential amplifier. Furthermore, the magnetoresistive element is biased by an induced magnetic anisotropy means in a predetermined direction.
Inventors
- 👤 Noboru Nomura
- 👤 Yasuharu Shimeki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:38
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3906; G11B5/3945; G11B5/3948; G11B5/3958; G11B5/3961; G11B5/3964; G11B5/399
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
183 words
A thin film magnetic head having a magnetoresistive element in which a thin ferromagnetic film is deposited on a substrate, wherein said magnetoresistive element has three terminals comprising two end terminals connected to means for providing a current flowing through the magnetoresistive element in one direction and an intermediate terminal connected to grounding means and the magnetization of the magnetoresistive element is preset by magnetization presetting means to be substantially inclined in one direction against the longitudinal direction of the magnetoresistive element; a change in resistance of a first portion between one of said two end terminals and said intermediate terminal and a change in resistance of a second portion between the other of said two end terminals and said intermediate terminal which are obtained by applying a magnetic field of a signal recorded on and reproduced from a single track of a magnetic recording medium are respectively obtained as reproduction voltages by flowing a current through said first and second portions in the same direction; and the two end terminals are connected to a differential amplifier which differentially amplifies the reproduction voltages.
Claim 2
Dependent Claim
183 words
A thin film magnetic head having a magnetoresistive element in which a thin ferromagnetic film is deposited on a substrate, wherein said magnetoresistive element has three terminals comprising two end terminals connected to means for providing a current flowing through the magnetoresistive element in one direction and an intermediate terminal connected to grounding means and the magnetization of the magnetoresistive element is preset by magnetization presetting means to be substantially inclined in one direction against the longitudinal direction of the magnetoresistive element; a change in resistance of a first portion between one of said two end terminals and said intermediate terminal and a change in resistance of a second portion between the other of said two end terminals and said intermediate terminal which are obtained by applying a magnetic field of a signal recorded on and reproduced from a single track of a magnetic recording medium are respectively obtained as reproduction voltages by flowing a current through said first and second portions in the same direction; and the two end terminals are connected to a differential amplifier which differentially amplifies the reproduction voltages.
Claim 3
Dependent Claim
53 words
A thin film magnetic head of claim 1 having a magnetoresistive element in which a thin ferromagnetic film is deposited on a substrate, wherein said magnetoresistive element has three terminals constituted by two end terminals and intermediate terminal and wherein the magnetization is preset by induced magnetic anisotropy produced in said magnetoresistive element.
Claim 4
Dependent Claim
69 words
A thin film magnetic head of claim 1 having a magnetoresistive element in which a thin ferromagnetic film is deposited on a substrate, wherein said magnetoresistive element has three terminals constituted by two end terminals and an intermediate terminal and wherein the magnetization is preset by induced magnetic anisotropy produced in said magnetoresistive element by a linear indentation pattern formed on at least one surface of said magnetoresistive element.
Claim 5
Dependent Claim
35 words
A head according to claim 2, wherein said induced magnetic anisotropy is produced by an anisotropic characteristic of a thermal expansion coefficient of said substrate and by magnetostriction incurred in said magnetoresistive element formed thereon.
Claim 6
Dependent Claim
153 words
A thin film magnetic head having a magnetoresistive element in which a thin ferromagnetic film is deposited on a substrate, wherein said magnetoresistive element has three terminals constituted by two end terminals and an intermediate terminal, and means providing a low AC impedance between said intermediate terminal and a source of reference potential, and is biased to be magnetized in one direction; a change in resistance of a first portion between one of said two end terminals and said intermediate terminal and a change in resistance of a second portion between the other of said two end terminals and said intermediate terminal which are obtained by applying a magnetic field of a signal recorded on and reproduced from a single track of a magnetic recording medium are respectively obtained as reproduction voltages by flowing a current through said first and second portions in the same direction; and the reproduction voltages are differentially amplified.
Claim 7
Dependent Claim
153 words
A thin film magnetic head having a magnetoresistive element in which a thin ferromagnetic film is deposited on a substrate, wherein said magnetoresistive element has three terminals constituted by two end terminals and an intermediate terminal, and means providing a low AC impedance between said intermediate terminal and a source of reference potential, and is biased to be magnetized in one direction; a change in resistance of a first portion between one of said two end terminals and said intermediate terminal and a change in resistance of a second portion between the other of said two end terminals and said intermediate terminal which are obtained by applying a magnetic field of a signal recorded on and reproduced from a single track of a magnetic recording medium are respectively obtained as reproduction voltages by flowing a current through said first and second portions in the same direction; and the reproduction voltages are differentially amplified.
Claim 8
Dependent Claim
35 words
A head according to claim 5, wherein the one of said two end terminals formed at said magnetoresistive element is grounded through a resistor, whereas the other of said two end terminals receives a current.
References Cited (Backward Citations)
US3019125A
Cited
US3232787A
Cited
US4040113A
Cited
US4271438A
Cited
US4361805A
Cited
US4394699A
Cited
US4477794A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |