US3710438A
Expired / Lapsed
US
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Method for making magnetic thin film heads with magnetic anisotropy
Assignee: International Business Machines Corp
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Filing: 1970-12-23
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Granted: 1973-01-16
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Expires: 1990-12-23
Abstract
Abstract A method for the batch fabrication of thin film magnetic heads with pole pieces having a preferred magnetic direction. The pole pieces are generated by growing, on a suitably oriented monocrystalline substrate, monocrystalline layers of zinc ferrite in zones corresponding to the respective geometrical form of the pole pieces, these layers having an inserted component (e.g. Ni) which renders the ferrite ferromagnetic. The Ni component may be added during the growing process or afterwards inserted in, or removed from homogeneous layers by a masked diffusion process.
Inventors
- 👤 E Max
- 👤 D Rogalla
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 04:01
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/187; G11B5/193; G11B5/31; G11B5/3103; G11B5/3163; 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: 10
Claim 1
Independent Claim
33 words
The method claimed in claim 1, wherein the monocrystalline zinc-ferrite layers are generated by high temperature hydrolysis of a compound selected from the class consisting of the chlorides and bromides of said component.
Claim 2
Dependent Claim
7 words
embedding conductive lOops in said layers; and
Claim 3
Dependent Claim
46 words
rendering the ferrite ferromagnetic by inserting a component into the zinc ferrite; the crystal surface of the substrate being arranged in such a manner that the magnetic preferential direction of the monocrystalline ferromagnetic ferrite thus formed adopts a predetermined direction with respect to the operation gap.
Claim 4
Dependent Claim
43 words
The method of claim 2, wherein the component rendering the monocrystalline zinc-ferrite layers ferromagnetic is selected from the class consisting of nickel and manganese, said component being applied while growing the monocrystalline zinc-ferrite film, and then subsequently diffusing said component into said film.
Claim 5
Dependent Claim
31 words
The method of claim 3, wherein growth of the monocrystalline zinc-ferrite layer is effected on a Spinell single crystal substrate having a surface suitably oriented with respect to the preferred crystallography.
Claim 6
Dependent Claim
71 words
The method of claim 4, further comprising the steps of: producing a first monocrystalline ferromagnetic nickel-zinc ferrite layer by growing said layer on said monocrystalline substrate through a mask defining the pole piece zones; subsequently applying conductive loops; and growing a second monocrystalline ferromagnetic ferrite layer on said first layer to cover the conductive loop in the region of the operation gap by means of a mask defining the pole pieces.
Claim 7
Dependent Claim
72 words
The method of claim 4, further comprising the steps of: applying a continuous, monocrystalline zinc-ferrite layer to a monocrystalline substrate; defining pole piece zones by means of a silicon dioxide mask applied onto the zinc-ferrite layer; diffusing nickel or manganese into aforesaid zones; applying conductive loops; growing a zinc-ferrite layer; and diffusing, through another silicon dioxide mask, a component from the class consisting of nickel and manganese in the pole piece zones.
Claim 8
Dependent Claim
78 words
The method of claim 4, further comprising the steps of: applying a continuous, monocrystalline, ferromagnetic nickel-zinc ferrite layer onto a monocrystalline substrate; exposing the zones surrounding the pole pieces by means of a first silicon dioxide mask applied onto the ferrite layer; rendering the ferromagnetic properties ineffective in these zones by diffusing zinc; applying a conductive loop; growing a nickel-zinc ferrite layer; and diffusing, through a second silicon dioxide mask, zinc into the zones surrounding the pole pieces.
Claim 9
Dependent Claim
27 words
The method of claim 7, wherein the conductive loops of the magnetic heads are applied by the vapor-deposition of nobel metals onto the ferrite layer through masks.
Claim 10
Dependent Claim
36 words
The method of claim 8, wherein a plurality of magnetic heads are made on a Spinell single crystal, forming the substrate, the crystal being separated, after the magnetic heads have been made, into smaller individual units.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-16 | 1976-07-17 | 1977-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-16 | 1980-07-17 | 1981-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-16 | 1984-07-17 | 1985-01-16 | $7700.00 | Window Closed / Lapsed |