Patent EP0335488A2 successfully refreshed from Google Patents.
EP0335488A2
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Magnetoresistive read transducer
Assignee: International Business Machines Corp
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Filing: 1989-02-15
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Granted: —
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Expires: 2009-02-15
Abstract
Abstract In a magnetoresistive (MR) read transducer comprising a thin MR film (10) formed of ferromagnetic material and a thin nonmagnetic spacer film layer (14) in contact with the MR film, the spacer film (14) comprises a material selected from the group consisting of nichrome and nichrome with chromium oxide. To make such a transducer, a thin soft magnetic material film is deposited in contact with the spacer film so that a transverse bias is produced in at least a part of the MR film. The resistivity of the spacer film can be chosen by selecting the ratio of nichrome to chromium oxide in the spacer film. In a specific embodiment (Fig. 2) the spacer film (24) extends over only the central region of the MR film (10). Where the MR film consists of a nickel based alloy, a wet chemical etching process using an etchant comprising an aqueous solution of ceric ammonium nitrate and acetic acid can be used to pattern the spacer film.
Inventors
- 👤 Robert Edward Fontana Jr.
- 👤 James Kent Howard
- 👤 James Hsi-Tang Lee
- 👤 Haralambos Lefakis
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-03 19:38
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
111 words
A magnetoresistive read transducer comprising a thin magnetoresistive film (10) formed of ferromagnetic material, a thin spacer film (14; 24) in contact with the magnetoresistive film, and a thin soft magnetic material film (13; 30) in contact with the spacer film so that the soft magnetic material film is positioned parallel to but spaced from the magnetoresistive film whereby a transverse bias can be produced in at least a part of the magnetoresistive film to maintain that part of the magnetoresistive film in a linear response mode, the transducer being characterised by the thin spacer film comprising a material selected from the group consisting of nichrome and nichrome with chromium oxide.
Claim 2
Dependent Claim
111 words
A magnetoresistive read transducer comprising a thin magnetoresistive film (10) formed of ferromagnetic material, a thin spacer film (14; 24) in contact with the magnetoresistive film, and a thin soft magnetic material film (13; 30) in contact with the spacer film so that the soft magnetic material film is positioned parallel to but spaced from the magnetoresistive film whereby a transverse bias can be produced in at least a part of the magnetoresistive film to maintain that part of the magnetoresistive film in a linear response mode, the transducer being characterised by the thin spacer film comprising a material selected from the group consisting of nichrome and nichrome with chromium oxide.
Claim 3
Dependent Claim
33 words
A megnetoresistive read transducer as claimed in claim 1, wherein the resistivity of the material of the spacer film is established by selecting the ratio of nichrome to chromium oxide in the material.
Claim 4
Dependent Claim
29 words
A magnetoresistive read transducer as claimed in claim 1 or claim 2, wherein the thin spacer film (24) extends over only the central region (28) of the magnetoresistive film.
Claim 5
Independent Claim
114 words
A method of making a magnetoresistive read transducer comprising the steps of: depositing a thin magnetoresistive film formed of ferromagnetic material onto a substrate; depositing a thin spacer film in contact with the said magnetoresistive film, the spacer film comprising a material selected from the group consisting of nichrome and nichrome with chromium oxide; and depositing a thin soft magnetic material film in contact with the spacer film so that the soft magnetic material film is positioned parallel to but spaced from the magnetoresistive film whereby a transverse bias can be produced in at least a part of the magnetoresistive film to maintain that part of the magnetoresistive film in a linear response mode.
Claim 6
Independent Claim
114 words
A method of making a magnetoresistive read transducer comprising the steps of: depositing a thin magnetoresistive film formed of ferromagnetic material onto a substrate; depositing a thin spacer film in contact with the said magnetoresistive film, the spacer film comprising a material selected from the group consisting of nichrome and nichrome with chromium oxide; and depositing a thin soft magnetic material film in contact with the spacer film so that the soft magnetic material film is positioned parallel to but spaced from the magnetoresistive film whereby a transverse bias can be produced in at least a part of the magnetoresistive film to maintain that part of the magnetoresistive film in a linear response mode.
Claim 7
Dependent Claim
45 words
A method of making a magnetoresistive read transducer as claimed in claim 4, additionally comprising, prior to the step of depositing the thin soft magnetic material film, patterning the thin spacer film so that it extends over only the central region of the magnetoresistive film.
Claim 8
Dependent Claim
22 words
A method of making a magnetoresistive read transducer as claimed in claim 5, wherein the magnetoresistive film comprises a nickel based alloy.
Claim 9
Dependent Claim
29 words
A method of making a magnetoresistive read transducer as claimed in claim 6, wherein the patterning step is carried out by the use of a wet chemical etching process.
Claim 10
Dependent Claim
36 words
A method of making a magnetoresistive read transducer as claimed in claim 7, wherein the wet chemical etching process is carried out by an etchant comprising an aqueous solution of ceric ammonium nitrate and acetic acid.
References Cited (Backward Citations)
No citation records indexed.
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