US5157570A
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US
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Magnetic pole configuration for high density thin film recording head
Assignee: Quantum Corp
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Filing: 1990-06-29
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Granted: 1992-10-20
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Expires: 2010-06-29
Abstract
Abstract A thin film magnetic recording head for high-density recording applications. The head includes a pole formed from at least two ferromagnetic material layers with one layer having high anisotropy (H k ) and low permeability (μ), and the other layer having low H k and high μ. The high H k layer provides the lower magnetic impedance flux path in the tip region and the low H k layer provides the lower magnetic impedance path in the yoke region of the head. A non-magnetic film may be disposed between the layers, with a thickness chosen to minimize domain flux coupling of the two magnetic layers, while allowing magnetic signal flux transfer between layers at an appropriate point between the tip and the yoke. The pole may be sculpted so that the low H k layer extends only partially into the tip region, or so that the high H k layer extends only partially into the yoke. Alternatively, the invention may use a laminated, high permeability layer and a homogeneous layer in place of the high H k and low H k layers.
Inventors
- 👤 Harold B. Shukovsky
- 👤 Sharat Batra
- 👤 Michael L. Mallary
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:00
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/31; G11B5/3109; G11B5/313; G11B5/3143; G11B5/3146; G11B5/3153; G11B5/3113; G11B5/3163
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
63 words
A magnetic recording head including a laminated pole member having a tip portion and a yoke portion, wherein the pole member comprises: a first flux-conductive layer having high anisotropy (H k ) and low permeability (μ); a second flux-conductive layer having low H k and high μ; and means for minimizing the domain flux coupling between the two layers in the tip portion.
Claim 2
Dependent Claim
63 words
A magnetic recording head including a laminated pole member having a tip portion and a yoke portion, wherein the pole member comprises: a first flux-conductive layer having high anisotropy (H k ) and low permeability (μ); a second flux-conductive layer having low H k and high μ; and means for minimizing the domain flux coupling between the two layers in the tip portion.
Claim 3
Dependent Claim
20 words
A magnetic recording head as in claim 1 additionally comprising: means for permitting signal flux coupling between the two layers.
Claim 4
Dependent Claim
28 words
A magnetic recording head as in claim 1 wherein the two layers of material are dimensioned to extend throughout both the tip and yoke portions of the pole.
Claim 5
Dependent Claim
24 words
A magnetic recording head as in claim 1 wherein the high H k layer is a homogeneous layer of high H k ferromagnetic material.
Claim 6
Dependent Claim
24 words
A magnetic recording head as in claim 1 wherein the low H k layer is a homogeneous layer of low H k ferromagnetic material.
Claim 7
Dependent Claim
22 words
A magnetic recording head as in claim 1 wherein the high H k layer is a homogeneous layer of nickel-iron-cobalt alloy (NiFeCo).
Claim 8
Dependent Claim
22 words
A magnetic recording head as in claim 1 wherein the low H k layer is a homogeneous layer of nickel-iron-cobalt alloy (NiFeCo).
Claim 9
Dependent Claim
22 words
A magnetic recording head as in claim 1 wherein the low H k layer is a homogeneous layer of nickel-iron alloy (NiFe).
Claim 10
Dependent Claim
29 words
A magnetic recording head as in claim 1 wherein the high H k layer has a lower magnetic impedance flux path than any other layer in the tip portion.
Claim 11
Dependent Claim
29 words
A magnetic recording head as in claim 1 wherein the low H k layer has a lower magnetic impedance flux path than any other layer in the yoke portion.
Claim 12
Dependent Claim
32 words
A magnetic recording head as in claim 1 wherein the means for minimizing the domain flux coupling between the two layers comprises: a non-magnetic layer, disposed between the first and second layers.
Claim 13
Dependent Claim
23 words
A magnetic recording head as in claim 11 wherein the non-magnetic layer is a layer of aluminum oxide (Al 2 O 3 ).
Claim 14
Dependent Claim
26 words
A magnetic recording head as in claim 11 wherein the non-magnetic layer has a thickness which minimizes domain flux coupling between the first and second layers.
Claim 15
Dependent Claim
40 words
A magnetic recording head as in claim 1 wherein the high H k layer is dimensioned to extend into both the tip and yoke portions, and the low H k layer is dimensioned to extend into the yoke portion only.
Claim 16
Dependent Claim
28 words
A magnetic recording head as in claim 14 additionally comprising: a non-magnetic layer, disposed between the two layers, and being dimensioned to extend into the yoke portion only.
Claim 17
Dependent Claim
49 words
A magnetic recording head as in claim 1 wherein the high H k layer is dimensioned to extend into the tip portion only, and the low H k layer is dimensioned to extend throughout the yoke portion and to overlap the high H k layer in the tip portion.
Claim 18
Dependent Claim
71 words
A magnetic recording head including a laminated pole member having a tip portion and a yoke portion, wherein the pole member comprises: a first flux-conductive homogeneous layer; a second flux-conductive laminated layer comprising a plurality of material laminae; and means for reducing the domain flux coupling in the tip portion between the two layers such that the amount of domain flux coupling is as though the layers were spaced far apart.
Claim 19
Dependent Claim
71 words
A magnetic recording head including a laminated pole member having a tip portion and a yoke portion, wherein the pole member comprises: a first flux-conductive homogeneous layer; a second flux-conductive laminated layer comprising a plurality of material laminae; and means for reducing the domain flux coupling in the tip portion between the two layers such that the amount of domain flux coupling is as though the layers were spaced far apart.
Claim 20
Dependent Claim
26 words
A magnetic recording head as in claim 17 wherein the H k of the homogeneous layer is chosen to optimize its performance in the yoke portion.
Claim 21
Dependent Claim
25 words
A magnetic recording head as in claim 17 wherein the permeability of the laminated layer is chosen to optimize its performance in the tip portion.
Claim 22
Dependent Claim
24 words
A magnetic recording head as in claim 17 wherein the laminae are formed from alternately spaced films of magnetically insulating and magnetically conductive material.
Claim 23
Dependent Claim
20 words
A magnetic recording head as in claim 20 wherein the magnetically insulating film material is Al 2 O 3 .
Claim 24
Dependent Claim
18 words
A magnetic recording head as in claim 20 wherein the magnetically conductive film material is an NiFeCo alloy.
Claim 25
Dependent Claim
19 words
A magnetic recording head as in claim 20 wherein the homogeneous layer is formed of a nickel-iron-cobalt alloy (NiFeCo).
Claim 26
Dependent Claim
20 words
A magnetic recording head as in claim 17 additionally comprising: a non-magnetic layer, disposed between the homogeneous and laminated layers.
Claim 27
Dependent Claim
29 words
A magnetic recording head as in claim 17 wherein the laminated layer extends into both the tip and yoke portions, and the homogeneous extends into the yoke portion only.
Claim 28
Dependent Claim
30 words
A magnetic recording head as in claim 25 additionally comprising: a non-magnetic layer, disposed between the homogeneous and laminated layers, and being dimensioned to extend into the yoke portion only.
Claim 29
Dependent Claim
36 words
A magnetic recording head as in claim 17 wherein the laminated layer extends into the tip portion only, and the homogeneous layer extends throughout the yoke portion and overlaps the laminated layer in the tip portion.
Claim 30
Dependent Claim
248 words
A magnetic recording device comprising: a magnetic storage disk; a first magnetically conductive pole member having a tip end and a yoke end, with the width of a first pole at the tip end defined by a desired number of tracks per inch (TPI); a second magnetically conductive pole member having a tip end and a yoke end, with the width of a second pole at the tip end defined by a desired TPI, the first and second pole members being joined at their yoke ends and being spaced apart at their tip ends; a magnetically non-magnetic gap layer, disposed between the first and second poles and defining the tip and spacing, the gap layer containing a plurality of electrical conductors disposed therein for connecting to electrical circuit coils, wherein each of the first and second pole members further comprises: a high H k , flux-conductive, high anisotropy (H k ) and low permeability (μ) layer, extending throughout the pole member from the tip end to the yoke end, the high H k layer providing the lowest impedance magnetic-flux path in the tip end; a low H k , flux-conductive, homogeneous layer formed of a low H k and high μ nickel-iron material, and extending through the pole member in the region of the yoke end only, the low H k layer providing the lowest impedance magnetic-flux path in the yoke end; and means for decoupling the two layers in terms of domain coupling at the tip end.
Claim 31
Dependent Claim
248 words
A magnetic recording device comprising: a magnetic storage disk; a first magnetically conductive pole member having a tip end and a yoke end, with the width of a first pole at the tip end defined by a desired number of tracks per inch (TPI); a second magnetically conductive pole member having a tip end and a yoke end, with the width of a second pole at the tip end defined by a desired TPI, the first and second pole members being joined at their yoke ends and being spaced apart at their tip ends; a magnetically non-magnetic gap layer, disposed between the first and second poles and defining the tip and spacing, the gap layer containing a plurality of electrical conductors disposed therein for connecting to electrical circuit coils, wherein each of the first and second pole members further comprises: a high H k , flux-conductive, high anisotropy (H k ) and low permeability (μ) layer, extending throughout the pole member from the tip end to the yoke end, the high H k layer providing the lowest impedance magnetic-flux path in the tip end; a low H k , flux-conductive, homogeneous layer formed of a low H k and high μ nickel-iron material, and extending through the pole member in the region of the yoke end only, the low H k layer providing the lowest impedance magnetic-flux path in the yoke end; and means for decoupling the two layers in terms of domain coupling at the tip end.
Claim 32
Dependent Claim
67 words
A magnetic recording device as in claim 28 wherein each pole additionally comprises: a flux-insulating layer, disposed between the high H k and low H k layers, the flux-insulating layer being formed of aluminum oxide (Al 2 O 3 ), and having a thickness which minimizes the domain flux conduction between the high H k and low H k layers, while allowing signal flux conduction between them.
Claim 33
Dependent Claim
26 words
A magnetic recording device as in claim 28 wherein the high H k layer is a homogeneous layer of a high H k , nickel-iron-cobalt material.
Claim 34
Dependent Claim
32 words
A magnetic recording device as in claim 28 wherein one of the layers is a laminate formed of alternating films of magnetically conductive NiFe and magnetically insulting Al 2 O 3 .
Claim 35
Dependent Claim
256 words
A magnetic recording head comprising: a first magnetically conductive pole member having a tip end and a yoke end, with the width of a first pole at the tip end defined by a desired number of tracks per inch (TPI); a second magnetically conductive pole member having a tip end and a yoke end, with the width of a second pole at the tip end defined by the desired TPI, the first and second poles members being joined at the in yoke ends and being spaced apart at the in tip ends; a magnetically non-magnetic gap layer, disposed between the first and second poles and defining the tip end spacing, the gap layer containing a plurality of electrical conductors disposed therein for connecting to electrical circuit coils, wherein each of the first and second pole members further comprises: a high H k , flux-conductive, high anisotropy (H k ) and low permeability (μ) layer, extending throughout the pole member from the tip end to the yoke end, the high H k layer providing the lowest impedance magnetic-flux path in the tip end; a low H k , flux-conductive, homogeneous layer formed of a low H k and high μ nickel-iron material, and extending through the pole member in the region of the yoke end only, the low H k layer providing the lowest impedance magnetic-flux path in the yoke end; and means for decoupling the two layers in terms of domain coupling at the tip end, and for blocking domain flux coupling between the two layers.
Claim 36
Dependent Claim
256 words
A magnetic recording head comprising: a first magnetically conductive pole member having a tip end and a yoke end, with the width of a first pole at the tip end defined by a desired number of tracks per inch (TPI); a second magnetically conductive pole member having a tip end and a yoke end, with the width of a second pole at the tip end defined by the desired TPI, the first and second poles members being joined at the in yoke ends and being spaced apart at the in tip ends; a magnetically non-magnetic gap layer, disposed between the first and second poles and defining the tip end spacing, the gap layer containing a plurality of electrical conductors disposed therein for connecting to electrical circuit coils, wherein each of the first and second pole members further comprises: a high H k , flux-conductive, high anisotropy (H k ) and low permeability (μ) layer, extending throughout the pole member from the tip end to the yoke end, the high H k layer providing the lowest impedance magnetic-flux path in the tip end; a low H k , flux-conductive, homogeneous layer formed of a low H k and high μ nickel-iron material, and extending through the pole member in the region of the yoke end only, the low H k layer providing the lowest impedance magnetic-flux path in the yoke end; and means for decoupling the two layers in terms of domain coupling at the tip end, and for blocking domain flux coupling between the two layers.
Claim 37
Dependent Claim
67 words
A magnetic recording head as in claim 29 wherein each pole additionally comprises: a flux-insulating layer, disposed between the high H k and low H k layers only in the yoke portion, the flux-insulating layer formed of aluminum oxide (Al 2 O 3 ), and the thickness of the flux-insulating layer such that magnetostatic coupling between the high H k and low H k layers is minimized.
Claim 38
Dependent Claim
27 words
A magnetic recording head as in claim 29 wherein the high H k layer is a homogeneous layer of a high H k , nickel-iron-cobalt (NiFeCo) material.
Claim 39
Dependent Claim
35 words
A magnetic recording head as in claim 29 wherein the high H k layer is a laminate formed of alternating films of magnetically conductive NiFe and magnetically insulating aluminum oxide (Al 2 O 3 ).
Claim 40
Dependent Claim
256 words
A magnetic recording head comprising: a first magnetically conductive pole member having a tip end and a yoke end, with the width of a first pole at the tip end defined by a desired number of tracks per inch (TPI); a second magnetically conductive pole member having a tip end and a yoke end, with the width of a second pole at the tip end defined by the desired TPI, the first and second poles being joined at their yoke ends and being spaced apart at their tip ends; a magnetically non-magnetic gap layer, disposed between the first and second poles and defining the tip end spacing, the gap layer containing a plurality of electrical conductors disposed therein for connecting to electrical circuit coils, wherein each of the first and second pole members further comprises: a high H k , flux-conductive, high anisotropy (H k ) and low permeability (μ) layer, extending into the region of the adjacent the tip end only, the high H k layer providing the lowest impedance magnetic-flux path in the tip end; a low H k , flux-conductive, homogeneous layer formed of a low H k and high μ nickel-iron material, and extending through the pole member from the tip end to the yoke end, the low H k layer providing the lowest impedance magnetic-flux path in the yoke end; and means for decoupling the two layers in terms of domain flux (near-field) coupling at the tip end, and for coupling the two layers in terms of signal flux (far-field) coupling.
Claim 41
Dependent Claim
256 words
A magnetic recording head comprising: a first magnetically conductive pole member having a tip end and a yoke end, with the width of a first pole at the tip end defined by a desired number of tracks per inch (TPI); a second magnetically conductive pole member having a tip end and a yoke end, with the width of a second pole at the tip end defined by the desired TPI, the first and second poles being joined at their yoke ends and being spaced apart at their tip ends; a magnetically non-magnetic gap layer, disposed between the first and second poles and defining the tip end spacing, the gap layer containing a plurality of electrical conductors disposed therein for connecting to electrical circuit coils, wherein each of the first and second pole members further comprises: a high H k , flux-conductive, high anisotropy (H k ) and low permeability (μ) layer, extending into the region of the adjacent the tip end only, the high H k layer providing the lowest impedance magnetic-flux path in the tip end; a low H k , flux-conductive, homogeneous layer formed of a low H k and high μ nickel-iron material, and extending through the pole member from the tip end to the yoke end, the low H k layer providing the lowest impedance magnetic-flux path in the yoke end; and means for decoupling the two layers in terms of domain flux (near-field) coupling at the tip end, and for coupling the two layers in terms of signal flux (far-field) coupling.
Claim 42
Dependent Claim
27 words
A magnetic recording head as in claim 36 wherein the high H k layer is a homogeneous layer of a high H k , nickel-iron-cobalt (NiFeCo) material.
Claim 43
Dependent Claim
35 words
A magnetic recording head as in claim 36 wherein the low H k layer is a laminate formed of alternating films of magnetically conductive NiFe and magnetically insulating aluminum oxide (Al 2 O 3 ).
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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) | 1995-10-20 | 1996-04-20 | 1996-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-20 | 2000-04-20 | 2000-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-20 | 2004-04-20 | 2004-10-20 | $7700.00 | Window Closed / Lapsed |