US4900650A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing a pole piece with improved magnetic domain structure
Assignee: Maxtor Corp
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Filing: 1988-05-12
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Granted: 1990-02-13
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Expires: 2008-05-12
Abstract
Abstract The mask through which the pole piece is deposited by through mask plating has a yoke region, a narrower pole tip region and a bulb region adjacent the pole tip region. The bulb region results in substantially uniform current density during the through mask plating which results in substantially uniform composition and thickness of the pole piece material across the pole piece. In particular, the composition difference between the pole tip and the yoke region is reduced from that according to prior art techniques. The combination of the composition uniformity and the different (than the prior art) stress distribution in the pole tip material results in favorable domain structure in the pole tip. The magnetic domains formed conduct flux by coherent rotation of the magnetization direction in the domains without changing the location of wall boundaries thereby reducing Barkhausen noise.
Inventors
- 👤 Shyam C. Das
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:22
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; G11B5/3163; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49034; Y10T29/49036; Y10T29/49043
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
53 words
Method of producing a thin film head made of a magnetic alloy having a pole tip region with desired magnetic domain structures comprising: forming a mask having a yoke region, a narrower pole tip region, and a bulb region adjacent the pole tip region; and through mask plating of the thin film head.
Claim 2
Dependent Claim
53 words
Method of producing a thin film head made of a magnetic alloy having a pole tip region with desired magnetic domain structures comprising: forming a mask having a yoke region, a narrower pole tip region, and a bulb region adjacent the pole tip region; and through mask plating of the thin film head.
Claim 3
Dependent Claim
61 words
Method of producing a thin film head made of a magnetic alloy having a pole tip region with desired magnetic domain structures comprising: forming a mask having a yoke region, a narrower pole tip region and a bulb region adjacent the pole tip region; and using sheet plating techniques followed by etching using the mask to produce the thin film head.
Claim 4
Dependent Claim
61 words
Method of producing a thin film head made of a magnetic alloy having a pole tip region with desired magnetic domain structures comprising: forming a mask having a yoke region, a narrower pole tip region and a bulb region adjacent the pole tip region; and using sheet plating techniques followed by etching using the mask to produce the thin film head.
Claim 5
Dependent Claim
56 words
Method of producing a thin film head made of a magnetic alloy having a pole tip region with desired magnetic domain structures comprising: forming a mask having a yoke region, a narrower pole tip region, and a bulb region adjacent the pole tip region; and using the mask to form pole piece geometry by vacuum deposition.
Claim 6
Dependent Claim
56 words
Method of producing a thin film head made of a magnetic alloy having a pole tip region with desired magnetic domain structures comprising: forming a mask having a yoke region, a narrower pole tip region, and a bulb region adjacent the pole tip region; and using the mask to form pole piece geometry by vacuum deposition.
Claim 7
Dependent Claim
21 words
The method of claim 1 or claim 2 or claim 3 wherein the mask is formed using photoresist and photolithographic techniques.
Claim 8
Dependent Claim
18 words
A thin film head made according to the method of claim 1 or claim 2 or claim 3.
Claim 9
Dependent Claim
24 words
The method of claim 1 or claim 2 or claim 3 further including magnetic annealing of the pole piece of the thin film head.
Claim 10
Dependent Claim
19 words
The method of claim 1 or claim 2 or claim 3 wherein the magnetic alloy is negative magnetostrictive NiFe.
Claim 11
Dependent Claim
17 words
The method of claim 1 or claim 2 or claim 3 wherein the magnetic alloy is NiFeCo.
Claim 12
Dependent Claim
19 words
The method of claim 1 or claim 2 or claim 3 wherein the magnetic alloy is a CoZr alloy.
References Cited (Backward Citations)
US3908194A
Cited
US4652954A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-12 | 1993-08-14 | 1994-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-12 | 1997-08-14 | 1998-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-12 | 2001-08-14 | 2002-02-13 | $7700.00 | Window Closed / Lapsed |