US5862022A
Expired / Lapsed
US
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Ferromagnetic tunnel junction, magnetoresistive element and magnetic head
Assignee: TDK Corp
•
Filing: 1997-09-19
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Granted: 1999-01-19
•
Expires: 2017-09-19
Abstract
Abstract This invention is directed to a ferromagnetic tunnel junction, an MR element and a magnetic head. A ferromagnetic tunnel junction is constituted by sequentially laminating a first ferromagnetic film, an insulating film and a second ferromagnetic film. These are laminated on an appropriate insulating substrate. The present invention is characterized in that the barrier potential of the insulating film is set within a range of 0.5 to 3 eV. A ferromagnetic tunnel junction with which a high MR ratio can be achieved with good reproduction characteristics is provided.
Inventors
- 👤 Kiyoshi Noguchi
- 👤 Taro Oike
- 👤 Satoru Araki
- 👤 Manabu Ohta
- 👤 Masashi Sano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:57
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/39; G11B5/3903; G11B5/3967; H; H10; H10N; H10N50/00; H10N50/10
Claims Analysis
Total Claims: 55
Claim 1
Independent Claim
37 words
A ferromagnetic tunnel junction constituted by sequentially laminating a first ferromagnetic film, an insulating film and a second ferromagnetic film, wherein: the barrier potential of said insulating film is within a range of 0.5 to 3 eV.
Claim 2
Dependent Claim
37 words
A ferromagnetic tunnel junction constituted by sequentially laminating a first ferromagnetic film, an insulating film and a second ferromagnetic film, wherein: the barrier potential of said insulating film is within a range of 0.5 to 3 eV.
Claim 3
Dependent Claim
25 words
A ferromagnetic tunnel junction according to claim 1, wherein: said barrier potential of said insulating film is within a range of 1.5 to 2.5 eV.
Claim 4
Dependent Claim
29 words
A ferromagnetic tunnel junction according to claim 1, wherein the coercivity of said first ferromagnetic film and the coercivity of said second ferromagnetic film are different from each other.
Claim 5
Dependent Claim
25 words
A ferromagnetic tunnel junction according to claim 1, wherein said first ferromagnetic film and said second ferromagnetic film are antiferromagnetically coupled via said insulating film.
Claim 6
Dependent Claim
33 words
A ferromagnetic tunnel junction according to claim 1, wherein said insulating film is constituted of an aluminum oxide film formed through heat treatment at 40 to 100 C in air after film formation.
Claim 7
Dependent Claim
19 words
A ferromagnetic tunnel junction according to claim 1, wherein: said insulating film is constituted of a diamond-like carbon film.
Claim 8
Dependent Claim
23 words
A ferromagnetic tunnel junction according to claim 1, wherein: the area of tunnel junction is at or less than 10 μm 2 .
Claim 9
Dependent Claim
52 words
A magnetoresistive element comprising: a ferromagnetic tunnel junction including an insulating film, a first ferromagnetic film and a second ferromagnetic film, with said first ferromagnetic film and said second ferromagnetic film laminated via said insulating film, the barrier potential of said insulating film being within a range of 0.5 to 3 eV.
Claim 10
Dependent Claim
52 words
A magnetoresistive element comprising: a ferromagnetic tunnel junction including an insulating film, a first ferromagnetic film and a second ferromagnetic film, with said first ferromagnetic film and said second ferromagnetic film laminated via said insulating film, the barrier potential of said insulating film being within a range of 0.5 to 3 eV.
Claim 11
Dependent Claim
24 words
A magnetoresistive element according to claim 8, wherein: said barrier potential of said insulating film is within a range of 1.5 to 2.5 eV.
Claim 12
Dependent Claim
28 words
A magnetoresistive element according to claim 8, wherein the coercivity of said first ferromagnetic film and the coercivity of said second ferromagnetic film are different from each other.
Claim 13
Dependent Claim
24 words
A magnetoresistive element according to claim 8, wherein: said first ferromagnetic film and said second ferromagnetic film are antiferromagnetically coupled via said insulating film.
Claim 14
Dependent Claim
32 words
A magnetoresistive element according to claim 8, wherein: said insulating film is constituted of an aluminum oxide film formed through heat treatment at 40° to 100° C. in air after film formation.
Claim 15
Dependent Claim
18 words
A magnetoresistive element according to claim 8, wherein: said insulating film is constituted of a diamond-like carbon film.
Claim 16
Dependent Claim
22 words
A magnetoresistive element according to claim 8, wherein: the area of tunnel junction is at or less than 10 μm 2 .
Claim 17
Dependent Claim
31 words
A magnetoresistive element according to claim 8, further comprising: a magnetic domain control film provided adjacent to both end portions of either said first ferromagnetic film or said second ferromagnetic film.
Claim 18
Dependent Claim
20 words
A magnetoresistive element according to claim 15, wherein: said magnetic domain control film is constituted of a hard ferromagnetic film.
Claim 19
Dependent Claim
18 words
A magnetoresistive element according to claim 16, wherein: said hard ferromagnetic film is constituted of a Co alloy.
Claim 20
Dependent Claim
26 words
A magnetoresistive element according to claim 17, wherein: said Co alloy is constituted of at least one alloy selected from CoPt, CoPtCr, CoPtTa, CoCrTa and CoPtTaCr.
Claim 21
Dependent Claim
19 words
A magnetoresistive element according to claim 15, wherein: said magnetic domain control film is constituted of an antiferromagnetic film.
Claim 22
Dependent Claim
24 words
A magnetoresistive element according to claim 19, wherein: said antiferromagnetic film is constituted of either a metallic antiferromagnetic material or an oxide antiferromagnetic material.
Claim 23
Dependent Claim
16 words
A magnetoresistive element according to claim 20, wherein: said metallic antiferromagnetic material is a Mn alloy.
Claim 24
Dependent Claim
31 words
A magnetoresistive element according to claim 21, wherein: said Mn alloy is constituted of at least one alloy selected from FeMn, NiMn, PtMn, RuMn, RhMn, IrMn, PdMn or an alloy thereof.
Claim 25
Dependent Claim
27 words
A magnetoresistive element according to claim 20, wherein: said oxide antiferromagnetic material is constituted of at least one of NiO, NiCoO or Fe 2 O 3 .
Claim 26
Dependent Claim
34 words
A magnetoresistive element according to claim 15, wherein: said magnetic easy axis of said ferromagnetic film provided with said magnetic domain control film extends perpendicular to the direction of said applied external magnetic field.
Claim 27
Dependent Claim
36 words
A magnetoresistive element according to claim 15, wherein: of said first ferromagnetic film and said second ferromagnetic film, said ferromagnetic film not provided with said magnetic domain control film is provided with a magnetization pinning film.
Claim 28
Dependent Claim
19 words
A magnetoresistive element according to claim 25, wherein: said magnetization pinning film is constituted of a hard ferromagnetic film.
Claim 29
Dependent Claim
18 words
A magnetoresistive element according to claim 25, wherein: said magnetization pinning film is constituted of an antiferromagnetic film.
Claim 30
Dependent Claim
70 words
A magnetoresistive element according to claim 25, wherein: of said first ferromagnetic film and said second ferromagnetic film, said magnetic easy axis of said ferromagnetic film provided with said magnetic domain control film extends perpendicular to a direction of said applied external magnetic field, whereas said magnetic easy axis of said ferromagnetic film provided with said magnetization pinning film extends parallel to said direction of said applied external magnetic field.
Claim 31
Dependent Claim
42 words
A magnetoresistive element according to claim 8, wherein: the direction of magnetization of said first ferromagnetic film and the direction of magnetization of said second ferromagnetic film are not parallel to each other when an applied external magnetic field is at zero.
Claim 32
Dependent Claim
32 words
A magnetoresistive element according to claim 24, wherein: said direction of magnetization of said first ferromagnetic film and said direction of magnetization of said second ferromagnetic film are perpendicular to each other.
Claim 33
Dependent Claim
33 words
A magnetoresistive element according to claim 8, wherein: a magnetic easy axis of said first ferromagnetic film and a magnetic easy axis of said second ferromagnetic film are not parallel to each other.
Claim 34
Dependent Claim
32 words
A magnetoresistive element according to claim 8, wherein: said magnetic easy axis of said first ferromagnetic film and said magnetic easy axis of said second ferromagnetic film are perpendicular to each other.
Claim 35
Dependent Claim
50 words
A magnetoresistive element according to claim 8, wherein: of said first ferromagnetic film and said second ferromagnetic film, either one has a magnetic easy axis extending perpendicular to an applied external magnetic field, with a magnetic easy axis of another ferromagnetic film extending parallel to said applied external magnetic field.
Claim 36
Dependent Claim
52 words
A magnetoresistive element according to claim 8, wherein: of said first ferromagnetic film and said second ferromagnetic film, the ferromagnetic film not provided with said magnetic domain control film is a hard ferromagnetic film with a coercivity higher than the coercivity of said ferromagnetic film provided with said magnetic domain control film.
Claim 37
Dependent Claim
82 words
A magnetic head comprising: a slider with an air bearing surface at a side thereof facing opposite a magnetic recording medium; and at least one magnetic conversion element having a ferromagnetic tunnel junction, said ferromagnetic tunnel junction including an insulating film, a first ferromagnetic film and a second ferromagnetic film with said first ferromagnetic film and said second ferromagnetic film being laminated via said insulating film, the barrier potential of said insulating film being within a range of 0.5 to 3 eV.
Claim 38
Dependent Claim
82 words
A magnetic head comprising: a slider with an air bearing surface at a side thereof facing opposite a magnetic recording medium; and at least one magnetic conversion element having a ferromagnetic tunnel junction, said ferromagnetic tunnel junction including an insulating film, a first ferromagnetic film and a second ferromagnetic film with said first ferromagnetic film and said second ferromagnetic film being laminated via said insulating film, the barrier potential of said insulating film being within a range of 0.5 to 3 eV.
Claim 39
Dependent Claim
24 words
A magnetic head according to claim 35, wherein: said barrier potential of said insulating film is within a range of 1.5 to 2.5 eV.
Claim 40
Dependent Claim
28 words
A magnetic head according to claim 35, wherein: the coercivity of said first ferromagnetic film and the coercivity of said second ferromagnetic film are different from each other.
Claim 41
Dependent Claim
24 words
A magnetic head according to claim 35, wherein: said first ferromagnetic film and said second ferromagnetic film are antiferromagnetically coupled via said insulating film.
Claim 42
Dependent Claim
32 words
A magnetic head according to claim 35 wherein: said insulating film is constituted of an aluminum oxide film formed through heat treatment at 40° to 100° C. in air after film formation.
Claim 43
Dependent Claim
18 words
A magnetic head according to claim 35 wherein: said insulating film is constituted of a diamond-like carbon film.
Claim 44
Dependent Claim
20 words
A magnetic head according to claim 35, wherein: the area of tunnel bonding is at or less than 11 μm.
Claim 45
Dependent Claim
44 words
A magnetic head according to claim 35, further comprising: an electrode film having a first electrode film and a second electrode film, with said first electrode film connected to said first ferromagnetic film and said second electrode film connected to said second ferromagnetic film.
Claim 46
Dependent Claim
38 words
A magnetic head according to claim 35, wherein: said first electrode film and said second electrode film are provided so that neither said first electrode film nor said second electrode film is exposed at said air bearing surface.
Claim 47
Dependent Claim
19 words
A magnetic head according to claim 43, wherein: said ferromagnetic tunnel junction is exposed at said air bearing surface.
Claim 48
Dependent Claim
14 words
A magnetic head according to claim 35, further comprising: an inductive magnetic conversion element.
Claim 49
Dependent Claim
55 words
A magnetic head according to claim 45, comprising: a bottom magnetic shield film and an upper magnetic shield film, said ferromagnetic tunnel junction being provided between said bottom magnetic shield film and said upper magnetic shield film, said upper magnetic shield film being constituted of a magnetic film provided at said inductive magnetic conversion element.
Claim 50
Dependent Claim
26 words
A magnetic head according to claim 35, wherein: a magnetic domain pinning film is provided at either said first ferromagnetic film or said second ferromagnetic film.
Claim 51
Dependent Claim
20 words
A magnetic head according to claim 47 wherein: said magnetic domain pinning film is constituted of a hard ferromagnetic film.
Claim 52
Dependent Claim
19 words
A magnetic head according to claim 47, wherein: said magnetic domain pinning film is constituted of an antiferromagnetic film.
Claim 53
Dependent Claim
38 words
A magnetic head according to claim 47 wherein: of said first ferromagnetic film and said second ferromagnetic film, a ferromagnetic film without said magnetic domain pinning film is provided with a magnetic domain control film at both ends.
Claim 54
Dependent Claim
20 words
A magnetic head according to claim 50, wherein: said magnetic domain control film is constituted of a hard ferromagnetic film.
Claim 55
Dependent Claim
39 words
A magnetic head according to claim 50, wherein: said magnetic domain control film is constituted of an antiferromagnetic film so that exchange coupling is formed between said first ferromagnetic film or said second ferromagnetic film and said antiferromagnetic film.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 7.5 Years (Year 8) | 2006-01-18 | 2006-07-20 | 2007-01-19 | $3760.00 | Window Closed / Lapsed |
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