US5032945A
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Magnetic thin film structures fabricated with edge closure layers
Assignee: International Business Machines Corp
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Filing: 1989-11-07
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Granted: 1991-07-16
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Expires: 2009-11-07
Abstract
Abstract Magnetic thin film structures are disclosed including a laminate of a layer of nonmagnetic material sandwiched between first and second layers of magnetic material and at least one edge closure layer of magnetic material disposed on a side edge of the laminate with the edge closure layer being in magnetic contact with the first and second layers of magnetic material. The edge closure layer eliminates magnetic edge closure domains and magnetic edge-curling walls in the yoke and poletip regions, or in a fluxguide of a magnetic recording head to substantially eliminate Barkhausen noise and wall network instabilities. Multiple layer laminates are also disclosed having a plurality of nonmagnetic layers each of which are sandwiched between layers of magnetic material and wherein the laminate includes edge closure layers that contact all the magnetic layers. Several methods are disclosed for fabricating the laminate. In one class of technique, the side edges are deposited together with a top layer in a single plating operation. In an another embodiment, the side edge closure layers are separately plated. Another embodiment provides for a layer of antiferromagnetic material deposited between the nonmagnetic layer and one of the magnetic layers to provide additional anisotropy.
Inventors
- 👤 Bernell E. Argyle
- 👤 Thomas C. Arnoldussen
- 👤 Thomas J. Beaulieu
- 👤 Dean A. Herman, Jr.
- 👤 Sol Krongelb
- 👤 Hin P. E. Lee
- 👤 Daniel A. Nepela
- 👤 Bojan Petek
- 👤 Lubomyr T. Romankiw
- 👤 John C. Slonczewski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:45
CPC Classifications
H; H01; H01F; H01F41/00; H01F41/32; H01F41/34; B; B82; B82Y; B82Y25/00; H01F10/00; H01F10/32; H01F10/324; H01F10/3268; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49021; Y10T29/49032; Y10T29/49034
Claims Analysis
Total Claims: 56
Claim 1
Independent Claim
56 words
A magnetic thin film structure comprising: a laminate of a nonmagnetic spacer layer sandwiched between first and second magnetic layers; and a first edge closure layer of magnetic material disposed on a first side edge of said laminate, said first edge closure layer being in magnetic contact with each of said first and second magnetic layers.
Claim 2
Dependent Claim
56 words
A magnetic thin film structure comprising: a laminate of a nonmagnetic spacer layer sandwiched between first and second magnetic layers; and a first edge closure layer of magnetic material disposed on a first side edge of said laminate, said first edge closure layer being in magnetic contact with each of said first and second magnetic layers.
Claim 3
Dependent Claim
51 words
The structure of claim 1 further including a second edge closure layer of magnetic material disposed on a second side edge of said laminate opposed to said first side edge, said second edge closure layer of magnetic material being in magnetic contact with each of said first and second magnetic layers.
Claim 4
Dependent Claim
12 words
The structure of claim 1 wherein said spacer layer comprises a conductor.
Claim 5
Dependent Claim
21 words
The structure of claim 3 wherein the conductor is one of NiP, Cu, a Cu alloy, Pd and a Pd alloy.
Claim 6
Dependent Claim
23 words
The structure of claim 1 wherein each of said magnetic layers and said edge-closure layer(s) comprise NiFe and said spacer layer comprises NiP.
Claim 7
Dependent Claim
21 words
The structure of claims 1 or 2 wherein each of said magnetic layers and said edge-closure layer(s) comprise a ferrimagnetic material.
Claim 8
Dependent Claim
12 words
The structure of claim 6 wherein the ferrimagnetic material is a ferrite.
Claim 9
Dependent Claim
14 words
The structure of claim 7 where the ferrite is one of MnZn and NiZn.
Claim 10
Dependent Claim
12 words
The structure of claim 1 wherein said spacer layer comprises an insulator.
Claim 11
Dependent Claim
19 words
The structure of claim 9 wherein the insulator is one of SiO 2 and Al 2 O 3 .
Claim 12
Dependent Claim
21 words
The structure of claims 1 or 2 wherein each of said magnetic layers and said edge-closure layer(s) comprise a ferromagnetic material.
Claim 13
Dependent Claim
13 words
The structure of claim 11 wherein the ferromagnetic material is a NiFe alloy.
Claim 14
Dependent Claim
11 words
The structure of claim 12 wherein the NiFe alloy is permalloy.
Claim 15
Dependent Claim
24 words
The structure of claim 11 further including an antiferromagnetic layer sandwiched between said spacer layer and one of said first and second magnetic layers.
Claim 16
Dependent Claim
31 words
The structure of claim 14 wherein said antiferromagnetic layer comprises an alloy of Mn and an element selected from the group consisting of Fe, Co, Cu, Ge, Ni, Pt and Rh.
Claim 17
Dependent Claim
28 words
The structure of claim 15 wherein each of said magnetic layers and said edge-closure layer(s) comprise NiFe, said spacer layer comprises NiP and said antiferromagnetic layer comprises FeMn.
Claim 18
Dependent Claim
31 words
The structure of claim 14 wherein said laminate includes opposed third and fourth side edges, said antiferromagnetic layer being spaced from at least one of said third and fourth side edges.
Claim 19
Dependent Claim
26 words
The structure of claim 17 wherein said antiferromagnetic layer is spaced from at least one of said third and fourth side edges by about 1 μm.
Claim 20
Dependent Claim
16 words
The structure of claim 14 wherein said structure comprises a portion of a magnetic recording head.
Claim 21
Dependent Claim
29 words
The structure of claim 19 wherein said structure comprises a yoke portion of a magnetic recording and at least one pole tip region in contact with said yoke portion.
Claim 22
Dependent Claim
11 words
The structure of claim 19 wherein said structure comprises a fluxguide.
Claim 23
Dependent Claim
18 words
The structure of claims 1 and 2 wherein said structure comprises a portion of a magnetic recording head.
Claim 24
Dependent Claim
30 words
The structure of claim 22 wherein said structure comprises a yoke portion of a magnetic recording head and at least one pole tip region in contact with said yoke portion.
Claim 25
Dependent Claim
11 words
The structure of claim 22 wherein said structure comprises a fluxguide.
Claim 26
Dependent Claim
61 words
A magnetic thin film structure comprising: a laminate of a plurality of nonmagnetic spacer layers, each of said spacer layers being sandwiched between a respective pair of magnetic layers a first edge closure layer of magnetic material disposed on a first side edge of said laminate, said first edge closure layer being in magnetic contact with each of said magnetic layers.
Claim 27
Dependent Claim
61 words
A magnetic thin film structure comprising: a laminate of a plurality of nonmagnetic spacer layers, each of said spacer layers being sandwiched between a respective pair of magnetic layers a first edge closure layer of magnetic material disposed on a first side edge of said laminate, said first edge closure layer being in magnetic contact with each of said magnetic layers.
Claim 28
Dependent Claim
48 words
The structure of claim 25 further including a second edge closure layer of magnetic material disposed on a second side edge of said laminate opposed to said first side edge, said second edge closure layer of magnetic material being in magnetic contact with each of said magnetic layers.
Claim 29
Dependent Claim
21 words
The structure of claim 25 or 26 wherein each of said magnetic layers and said edge-closure layer(s) comprise a ferromagnetic material.
Claim 30
Dependent Claim
11 words
The structure of claim 27 wherein the ferromagnetic material is NiFe.
Claim 31
Dependent Claim
10 words
The structure of claim 28 wherein the NiFe is permalloy.
Claim 32
Dependent Claim
19 words
The structure of claim 27 further including an antiferromagnetic layer sandwiched between said magnetic layers separating said spacer layers.
Claim 33
Dependent Claim
33 words
The structure of claim 30 wherein each of said antiferromagnetic layers comprises an alloy of Mn and an element selected from the group consisting of Fe, Co, Cu, Ge, Ni, Pt and Rh.
Claim 34
Dependent Claim
32 words
The structure of claim 31 wherein each of said magnetic layers and said edge-closure layer(s) comprise NiFe, each of said spacer layers comprises NiP and each of said antiferromagnetic layers comprises FeMn.
Claim 35
Dependent Claim
16 words
The structure of claim 30 wherein said structure comprises a portion of a magnetic recording head.
Claim 36
Dependent Claim
30 words
The structure of claim 33 wherein said structure comprises a yoke portion of a magnetic recording head and at least one pole tip region in contact with said yoke portion.
Claim 37
Dependent Claim
11 words
The structure of claim 33 wherein said structure comprises a fluxguide.
Claim 38
Dependent Claim
31 words
The structure of claim 30 wherein said laminate includes opposed third and fourth side edges, said antiferromagnetic layer being spaced from at least one of said third and fourth side edges.
Claim 39
Dependent Claim
26 words
The structure of claim 36 wherein said antiferromagnetic layer is spaced from at least one of said third and fourth side edges by about 1 μm.
Claim 40
Dependent Claim
21 words
The structure of claims 25 or 26 wherein each of said magnetic layers and said edge-closure layer(s) comprise a ferrimagnetic material.
Claim 41
Dependent Claim
12 words
The structure of claim 38 wherein the ferrimagnetic material is a ferrite.
Claim 42
Dependent Claim
14 words
The structure of claim 39 where the ferrite is one of MnZn and NiZn.
Claim 43
Dependent Claim
14 words
The structure of claim 25 wherein each of said spacer layers comprises an insulator.
Claim 44
Dependent Claim
19 words
The structure of claim 41 wherein the insulator is one of SiO 2 and Al 2 O 3 .
Claim 45
Dependent Claim
14 words
The structure of claim 25 wherein each of the spacer layers comprises a conductor.
Claim 46
Dependent Claim
17 words
The structure of claim 43 wherein the conductor is one of NiP, Cu and a Cu alloy.
Claim 47
Dependent Claim
25 words
The structure of claim 25 wherein each of said magnetic layers and said edge-closure layer(s) comprise NiFe and each of said spacer layers comprise NiP.
Claim 48
Dependent Claim
18 words
The structure of claims 14 or 15 wherein said structure comprises a portion of a magnetic recording head.
Claim 49
Dependent Claim
30 words
The structure of claim 46 wherein said structure comprises a yoke portion of a magnetic recording head and at least one pole tip region in contact with said yoke portion.
Claim 50
Dependent Claim
11 words
The structure of claim 46 wherein said structure comprises a fluxguide.
Claim 51
Dependent Claim
28 words
The structure of claims 25 or 26 wherein said laminate comprises alternate layers of magnetic and nonmagnetic material with the number of magnetic layers being an even number.
Claim 52
Dependent Claim
46 words
The structure of claims 25 or 26 when said laminate includes a top and bottom magnetic layer of a first thickness and at least one intermediate magnetic layer, each of said at least one intermediate magnetic layers being about double the thickness of said first thickness.
Claim 53
Dependent Claim
15 words
The structure of claim 50 when said edge closure layer is of said first thickness.
Claim 54
Dependent Claim
29 words
The structure of claims 1, 2, 25 or 26 wherein each of said magnetic layers and edge closure layers carry a substantially identical amount of magnetic flux in saturation.
Claim 55
Dependent Claim
26 words
The structure of claim 52 where each of said magnetic layers comprises a ferromagnetic material and each of said edge closure layers comprises a ferrimagnetic material.
Claim 56
Dependent Claim
26 words
The structure of claim 52 where each of said magnetic layers comprises a ferrimagnetic material and each of said edge closure layers comprises a ferromagnetic material.
References Cited (Backward Citations)
US4103315A
Cited
US4907113A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-07-15 | 1995-01-14 | 1995-07-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-07-15 | 1999-01-14 | 1999-07-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-07-15 | 2003-01-14 | 2003-07-16 | $7700.00 | Window Closed / Lapsed |