US4918554A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for making a shielded magnetoresistive sensor
Assignee: HGST Netherlands BV
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Filing: 1988-09-27
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Granted: 1990-04-17
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Expires: 2008-09-27
Abstract
Abstract The method for making a shielded magnetoresistive (MR) sensor in which the first shield is made of sendust and the second shield is made of permalloy. The method comprises the stages of depositing a layer of sendust to form a first shield; heat treating the sendust layer at a temperature greater than 400° C.; depositing a first electrically insulating layer; depositing, in the presence of a magnetic field, a MR layer; depositing a second layer of electrically insulating material; and, depositing a layer of permalloy to form the second shield.
Inventors
- 👤 Christopher H. Bajorek
- 👤 Cheng T. Horng
- 👤 Edward T. Yen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 22:52
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49034; Y10T29/49036; Y10T29/49043; Y10T29/49044
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
158 words
The method for making a shielded magnetoresistive sensor comprising the steps of: depositing a layer of a magnetic alloy comprising 3 to 6% aluminum, 6 to 12% silicon and the remainder iron to form a first shield member; heat treating said layer of a magnetic alloy at a temperature greater than 400° C. for a predetermined time to enhance the magnetic properties of said first shield member; depositing a first layer of a suitable electrically insulating material over said first shield member; depositing, in the presence of a magnetic field, a thin film of a magnetoresistive conductive layer formed of a magnetic material, said magnetic field being operable to orient said layer of magnetic material in a preferred direction; depositing a second layer of a suitable electrically insulating material over said layer of magnetoresistive material; and depositing a layer of soft magnetic material over said second layer of said electrically insulating material to form a second shield member.
Claim 2
Independent Claim
158 words
The method for making a shielded magnetoresistive sensor comprising the steps of: depositing a layer of a magnetic alloy comprising 3 to 6% aluminum, 6 to 12% silicon and the remainder iron to form a first shield member; heat treating said layer of a magnetic alloy at a temperature greater than 400° C. for a predetermined time to enhance the magnetic properties of said first shield member; depositing a first layer of a suitable electrically insulating material over said first shield member; depositing, in the presence of a magnetic field, a thin film of a magnetoresistive conductive layer formed of a magnetic material, said magnetic field being operable to orient said layer of magnetic material in a preferred direction; depositing a second layer of a suitable electrically insulating material over said layer of magnetoresistive material; and depositing a layer of soft magnetic material over said second layer of said electrically insulating material to form a second shield member.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein said layer of magnetic alloy comprises sendust.
Claim 4
Dependent Claim
19 words
The method of claim 1 wherein said layer of magnetic alloy additionally comprises 3% nickel to form super sendust.
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein said soft magnetic material is NiFe.
Claim 6
Dependent Claim
13 words
The method of claim 2 wherein said soft magnetic material is Ni Fe.
Claim 7
Dependent Claim
25 words
The method of claim 2 wherein said heat treatment is carried out at a temperature of 450°-500° C. for a time of about two hours.
Claim 8
Dependent Claim
25 words
The method of claim 3 wherein said heat treatment is carried out at a temperature of 450°-500° C. for a time of about two hours.
Claim 9
Dependent Claim
11 words
A shielded MR sensor produced by the method of claim 1.
Claim 10
Dependent Claim
11 words
A shielded MR sensor produced by the method of claim 6.
Claim 11
Dependent Claim
11 words
A shielded MR sensor produced by the method of claim 7.
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) | 1993-04-16 | 1993-10-16 | 1994-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-16 | 1997-10-16 | 1998-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-16 | 2001-10-16 | 2002-04-17 | $7700.00 | Window Closed / Lapsed |