US6312840B1
Expired / Lapsed
US
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Magnetic tunneling element and manufacturing method therefor
Assignee: Sony Corp
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Filing: 1999-09-16
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Granted: 2001-11-06
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Expires: 2019-09-16
Abstract
Abstract A magnetic tunnelling element in which the tunnel current flows reliably in an insulating layer to exhibit a stable magnetic tunnelling effect. To this end, the magnetic tunnelling element at least includes a first magnetic layer, a tunnel barrier layer formed on the first magnetic layer and a second magnetic layer formed on the tunnel barrier layer. The tunnel current flows via the tunnel barrier layer between the first magnetic metal layer and the second magnetic metal layer. The surface of the first magnetic layer carrying the tunnel barrier layer has a surface roughness (Ra) of 0.3 nm or less.
Inventors
- 👤 Seiji Kumagai
- 👤 Eiji Nakashio
- 👤 Junichi Sugawara
- 👤 Yoshito Ikeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:55
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/02; G01R33/06; G01R33/09; G01R33/093; B; B82; B82Y; B82Y25/00; B82Y10/00; B82Y40/00; G01R33/098; G11; G11B; G11B5/00; G11B5/127; G11B5/33; G11B5/332; G11B5/39; G11B5/3903; H; H01; H01F; H01F10/00; H01F10/32; H01F10/324; H01F10/3254; H01F41/00; H01F41/14; H01F41/30; H01F41/302; H01F41/305; H01F41/307; H10; H10N; H10N50/00; H10N50/10; G11B2005/3996; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/11; Y10T428/1107; Y10T428/1114; Y10T428/1193
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
98 words
A magnetic tunnelling element comprising: a first magnetic layer having a surface; a tunnel barrier layer formed on the surface of the first magnetic layer; and a second magnetic layer formed on the tunnel on the tunnel barrier layer, wherein the tunnel barrier layer has a tunnel current which flows between the first magnetic layer and the second magnetic layer when a potential is present across the first magnetic layer and the second magnetic layer; and the surface of the first magnetic layer carrying the tunnel barrier layer has a surface roughness (Ra) of 0.3 nm or less.
Claim 2
Dependent Claim
98 words
A magnetic tunnelling element comprising: a first magnetic layer having a surface; a tunnel barrier layer formed on the surface of the first magnetic layer; and a second magnetic layer formed on the tunnel on the tunnel barrier layer, wherein the tunnel barrier layer has a tunnel current which flows between the first magnetic layer and the second magnetic layer when a potential is present across the first magnetic layer and the second magnetic layer; and the surface of the first magnetic layer carrying the tunnel barrier layer has a surface roughness (Ra) of 0.3 nm or less.
Claim 3
Dependent Claim
28 words
The magnetic tunnelling element according to claim 1 , wherein the first magnetic layer is formed on a metal film serving as an electrode for the tunnel current.
Claim 4
Dependent Claim
24 words
The magnetic tunnelling element according to claim 2 , wherein the first magnetic layer has transcribed thereon a surface shape of said metal film.
Claim 5
Independent Claim
79 words
A method for manufacturing a magnetic tunnelling element at least including a first magnetic metal layer, a tunnel barrier layer and a second magnetic metal layer, laminated together, comprising the steps of: forming the first magnetic layer to have a major surface with an average roughness (Ra) of 0.3 nm or less; forming the tunnel barrier layer on the major surface of the first magnetic metal layer; and forming the second magnetic metal layer on the tunnel barrier layer.
Claim 6
Independent Claim
79 words
A method for manufacturing a magnetic tunnelling element at least including a first magnetic metal layer, a tunnel barrier layer and a second magnetic metal layer, laminated together, comprising the steps of: forming the first magnetic layer to have a major surface with an average roughness (Ra) of 0.3 nm or less; forming the tunnel barrier layer on the major surface of the first magnetic metal layer; and forming the second magnetic metal layer on the tunnel barrier layer.
Claim 7
Dependent Claim
33 words
The method for manufacturing a magnetic tunnelling element according to claim 4 , wherein the first magnetic metal layer is formed by a high frequency inductive coupling RF plasma supporting magnetron sputtering method.
Claim 8
Dependent Claim
101 words
A magnetic head having a magnetic tunnelling element at least including a first magnetic layer having a surface, a tunnel barrier layer formed on the surface of the first magnetic layer and a second magnetic layer formed on the tunnel barrier layer, wherein the tunnel barrier layer has a tunnel current which flows between the first magnetic layer and the second magnetic layer when a potential is present across the first magnetic layer and the second magnetic layer; and the surface of the first magnetic layer carrying the tunnel barrier layer has a surface roughness (Ra) of 0.3 nm or less.
Claim 9
Dependent Claim
101 words
A magnetic head having a magnetic tunnelling element at least including a first magnetic layer having a surface, a tunnel barrier layer formed on the surface of the first magnetic layer and a second magnetic layer formed on the tunnel barrier layer, wherein the tunnel barrier layer has a tunnel current which flows between the first magnetic layer and the second magnetic layer when a potential is present across the first magnetic layer and the second magnetic layer; and the surface of the first magnetic layer carrying the tunnel barrier layer has a surface roughness (Ra) of 0.3 nm or less.
Claim 10
Dependent Claim
30 words
The magnetic tunnelling element according to claim 1 , wherein the tunnel current remains constant when the potential across the first magnetic layer and the second magnetic layer is varied.
Claim 11
Dependent Claim
56 words
The magnetic tunnelling element according to claim 1 , wherein the first magnetic layer has a magnetization with a direction that is free to change in the presence of an external magnetic field; and the second magnetic layer has a magnetization with a predetermined direction that is fixed in the presence of an external magnetic field.
Claim 12
Dependent Claim
42 words
The magnetic tunnelling element according to claim 8 , wherein the first magnetic layer comprises a first magnetic sublayer and a second magnetic sublayer disposed on the first magnetic sublayer, the second magnetic sublayer forming the surface of the first magnetic layer.
Claim 13
Dependent Claim
29 words
The magnetic tunnelling element according to claim 9 , wherein the second magnetic sublayer is formed to have a substantially higher spin polarization ratio than the first magnetic sublayer.
Claim 14
Dependent Claim
23 words
The magnetic tunnelling element according to claim 10 , wherein the second magnetic sublayer comprises Cobalt and the first magnetic sublayer comprises NiFe.
Claim 15
Dependent Claim
36 words
The magnetic tunnelling element according to claim 8 , wherein the second magnetic layer comprises a first magnetic sublayer formed on said tunnel barrier layer and a second magnetic sublayer formed on the first magnetic sublayer.
Claim 16
Dependent Claim
29 words
The magnetic tunnelling element according to claim 12 , wherein the first magnetic sublayer is formed to have a substantially higher spin polarization ratio than the second magnetic sublayer.
Claim 17
Dependent Claim
23 words
The magnetic tunnelling element according to claim 13 , wherein the first magnetic sublayer comprises Cobalt and the second magnetic sublayer comprises NiFe.
Claim 18
Dependent Claim
35 words
The method for manufacturing a magnetic tunnelling element according to claim 4 , wherein the major surface of the first magnetic metal layer is formed to have an average roughness of 0.15 nm or less.
Claim 19
Dependent Claim
76 words
The method for manufacturing a magnetic tunnelling element according to claim 4 , wherein the step of forming the first magnetic layer comprises the steps of: forming a first magnetic sublayer; forming a second magnetic sublayer that is disposed on the first magnetic sublayer and that forms the major surface of the first magnetic layer; and wherein the second magnetic sublayer is formed to have a substantially higher spin polarization ratio than the first magnetic sublayer.
Claim 20
Dependent Claim
27 words
The method for manufacturing a magnetic tunnelling element according to claim 16 , wherein the first magnetic sublayer comprises NiFe and the second magnetic sublayer comprises Co.
Claim 21
Dependent Claim
68 words
The method for manufacturing a magnetic tunnelling element according to claim 4 , wherein the step of forming the first magnetic layer comprises the steps of: forming a first magnetic sublayer on the tunnel barrier layer; and forming a second magnetic sublayer disposed on the first magnetic sublayer wherein the first magnetic sublayer is formed to have a substantially higher spin polarization ratio than the second magnetic sublayer.
Claim 22
Dependent Claim
27 words
The method for manufacturing a magnetic tunnelling element according to claim 18 , wherein the second magnetic sublayer comprises NiFe and the first magnetic sublayer comprises Co.
References Cited (Backward Citations)
US5764567A
Cited
EP0898315A1
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) | 2004-11-05 | 2005-05-07 | 2005-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-11-05 | 2009-05-07 | 2009-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-11-05 | 2013-05-07 | 2013-11-06 | $7700.00 | Window Closed / Lapsed |