US3840865A
Expired / Lapsed
US
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Detection of magnetic domains by tunnel junctions
Assignee: International Business Machines Corp
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Filing: 1972-06-23
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Granted: 1974-10-08
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Expires: 1992-06-23
Abstract
Abstract Tunnel junctions are used to detect magnetic domains, such as bubble domains, using the change in Fermi level of one (or both) electrodes due to the magnetic field of the domain. The Fermi level shift causes the tunnel barrier height to change, leading to a change in tunneling conductance which is detectable as a current or voltage change. A simple tunnel junction in flux coupling proximity to the magnetic domains is suitable, but more sensitive detectors are made using Schottky barrier junctions, and magnetic semiconductors which exhibit conduction band splitting due to the stray field of the domains. In another embodiment, the magnetic sheet supporting the domains provides the tunnel barrier for sensing of the domains within it. Detection of submicron domains is easily achieved.
Inventors
- 👤 F Holtzberg
- 👤 Molnar S Von
- 👤 A Mayadas
- 👤 W Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:46
CPC Classifications
H; H10; H10D; H10D48/00; H10D48/40; G; G01; G01R; G01R33/00; G01R33/02; G01R33/06; G11; G11B; G11B5/00; G11C; G11C11/00; G11C11/02; G11C11/16; G11C11/165; G11C11/1673; G11C19/00; G11C19/02; G11C19/08; G11C19/0866; H10D99/00
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
77 words
A magnetic domain device, comprising: a magnetic medium in which said domains exist, a sensing device for detection of said domains, said sensing device including a Schottky barrier tunnel junction whose tunnel resistance depends on the presence and absence of said domains sufficiently close to said sensing device that the stray magnetic field of said domains intercepts said tunnel junction, means for sensing the change in tunnel resistance of said tunnel junction, for detection of magnetic domains.
Claim 2
Dependent Claim
77 words
A magnetic domain device, comprising: a magnetic medium in which said domains exist, a sensing device for detection of said domains, said sensing device including a Schottky barrier tunnel junction whose tunnel resistance depends on the presence and absence of said domains sufficiently close to said sensing device that the stray magnetic field of said domains intercepts said tunnel junction, means for sensing the change in tunnel resistance of said tunnel junction, for detection of magnetic domains.
Claim 3
Dependent Claim
20 words
The apparatus of claim 1, where said sensing device also includes means for providing electrical carriers through said tunnel junction.
Claim 4
Dependent Claim
15 words
The apparatus of claim 1, where said Schottky barrier si comprised of a conductor-semiconductor structure.
Claim 5
Dependent Claim
12 words
The apparatus of claim 3, where said semiconductor has a magnetic moment.
Claim 6
Dependent Claim
13 words
The apparatus of claim 3, where said conductor is comprised of a metal.
Claim 7
Dependent Claim
20 words
The apparatus of claim 1, where said sensing device includes a magnetic insulator and a conductor forming said tunnel junction.
Claim 8
Dependent Claim
17 words
The apparatus of claim 1, where said sensing device has a conductor-insulator-conductor structure forming said tunnel junction.
Claim 9
Dependent Claim
17 words
The apparatus of claim 1, where said sensing device includes a conductor-semiconductor structure forming said tunnel junction.
Claim 10
Dependent Claim
17 words
The apparatus of claim 1, where said sensing device includes a semiconductor-insulator-semiconductor structure forming said tunnel junction.
Claim 11
Dependent Claim
17 words
The apparatus of claim 1, where said sensing device includes a conductor-insulator-semiconductor structure forming said tunnel junction.
Claim 12
Dependent Claim
28 words
The apparatus of claim 1, where said tunnel junction has a planar geometry which is substantially parallel to a component of the stray magnetic field from said domains.
Claim 13
Dependent Claim
28 words
The apparatus of claim 1, where said magnetic medium is a magnetic sheet capable of supporting magnetic bubble domains therein, and said magnetic domains are magnetic bubble domains.
Claim 14
Dependent Claim
41 words
The apparatus of claim 12, where said magnetic sheet is contacted by conductors to form at least one tunnel junction the resistance of which changes when stray magnetic fields from bubble domains in said magnetic sheet couple to said tunnel junction.
Claim 15
Dependent Claim
12 words
The apparatus of claim 1, where said sensing device includes magnetic semiconductor.
Claim 16
Dependent Claim
22 words
The apparatus of claim 14, where said sensing device also includes a conductor which makes a Schottky barrier with said magnetic semiconductor.
Claim 17
Dependent Claim
73 words
An information handling apparatus using magnetic domains as representative of information comprising: a magnetic medium in which said domains exist, a sensing element having a Schottky barrier tunnel junction therein whose resistance depends on the magnetIc flux coupling it from said magnetic domains, means for providing an electrical current through said tunnel junction, detection means responsive to the resistance of said sensing element for detection of the presence and absence of said domains.
Claim 18
Dependent Claim
73 words
An information handling apparatus using magnetic domains as representative of information comprising: a magnetic medium in which said domains exist, a sensing element having a Schottky barrier tunnel junction therein whose resistance depends on the magnetIc flux coupling it from said magnetic domains, means for providing an electrical current through said tunnel junction, detection means responsive to the resistance of said sensing element for detection of the presence and absence of said domains.
Claim 19
Dependent Claim
15 words
The apparatus of claim 16, where said sensing element is comprised of a conductor-insulator-semiconductor structure.
Claim 20
Dependent Claim
17 words
The apparatus of claim 16, including conducting elements which form said tunnel junction with said magnetic medium.
Claim 21
Dependent Claim
15 words
The apparatus of claim 16, where said sensing element is comprised of a conductor-insulator-conductor structure.
Claim 22
Dependent Claim
15 words
The apparatus of claim 16, where said sensing element is comprised of a conductor-semiconductor structure.
Claim 23
Dependent Claim
15 words
The apparatus of claim 16, where said sensing element is comprised of a semiconductor-insulator-semiconductor structure.
Claim 24
Dependent Claim
13 words
The apparatus of claim 16, where said sensing element includes a magnetic semiconductor.
Claim 25
Dependent Claim
18 words
The apparatus of claim 22, further including a conductor which forms a Schottky barrier with said magnetic semiconductor.
Claim 26
Dependent Claim
90 words
A magnetic bubble domain apparatus, comprising: a magnetic sheet in which said domains exist, a sensing element comprised of a Schottky barrier tunnel junction located in flux-coupling proximity to domains in said sheet, the tunnel resistance of said tunnel junction being dependent upon the presence and absence of domains in flux coupling proximity to said sensing element, means for providing electrical carriers in said sensing element, detection means responsive to the tunnel resistance of said tunnel junction for detection of the presence and absence of domains in flux-coupling proximity thereto.
Claim 27
Dependent Claim
90 words
A magnetic bubble domain apparatus, comprising: a magnetic sheet in which said domains exist, a sensing element comprised of a Schottky barrier tunnel junction located in flux-coupling proximity to domains in said sheet, the tunnel resistance of said tunnel junction being dependent upon the presence and absence of domains in flux coupling proximity to said sensing element, means for providing electrical carriers in said sensing element, detection means responsive to the tunnel resistance of said tunnel junction for detection of the presence and absence of domains in flux-coupling proximity thereto.
Claim 28
Dependent Claim
21 words
The apparatus of claim 24, further including propagation means for moving said domains into flux coupling proximity to said sensing element.
Claim 29
Dependent Claim
15 words
The apparatus of claim 24, where said tunnel junction is a Schottky barrier tunnel junction.
Claim 30
Dependent Claim
13 words
The apparatus of claim 24, where said sensing element includes a magnetic semiconductor.
Claim 31
Dependent Claim
21 words
The apparatus of claim 27, where said sensing element includes a conductor which forms a Schottky barrier with said magnetic semiconductor.
Claim 32
Dependent Claim
19 words
The apparatus of claim 24, where said sensing element is comprised of a conductor-insulator-conductor structure forming said tunnel junction.
Claim 33
Dependent Claim
19 words
The apparatus of claim 24, where said sensing element is comprised of a conductor-semiconductor structure forming said tunnel junction.
Claim 34
Dependent Claim
18 words
Apparatus of claim 24, where said sensing element is comprised of a semiconductor-insulator-semiconductor structure forming said tunnel junction.
Claim 35
Dependent Claim
19 words
The apparatus of claim 24, where said sensing element is comprised of a conductor-insulator-semiconductor structure forming said tunnel junction.
Claim 36
Dependent Claim
21 words
The apparatus of claim 24, where said tunnel junction has a planar geometry which is substantially parallel to said magnetic sheet.
Claim 37
Dependent Claim
21 words
The apparatus of claim 24, where said tunnel junction has a planar geometry which is substantially perpendicular to said magnetic sheet.
Claim 38
Dependent Claim
19 words
The apparatus of claim 24, further including bias means for stabilizing the size of domains in said magnetic sheet.
Claim 39
Dependent Claim
15 words
The apparatus of claim 24, where said Schottky barrier is comprised of a conductor-semiconductor structure.
Claim 40
Dependent Claim
12 words
The apparatus of claim 36, where said semiconductor has a magnetic moment.
Claim 41
Dependent Claim
13 words
The apparatus of claim 36, where said conductor is comprised of a metal.
Claim 42
Dependent Claim
105 words
A magnetic bubble domain apparatus, comprising: a magnetic sheet in which said bubble domains exist, conductor means electrically contacting said sheet, there being a Schottky barrier tunnel junction formed between said sheet and at least one of said conductors, where the resistance of said tunnel junction depends upon the presence and absence of magnetic bubble domains in flux-coupling proximity thereto, means for providing domains in flux-coupling proximity to said tunnel junction, means for Providing electrical carriers through said tunnel junction, means for detecting the resistance of said tunnel junction indicating the presence and absence of magnetic bubble domains in flux-coupling proximity to said tunnel junction.
Claim 43
Dependent Claim
105 words
A magnetic bubble domain apparatus, comprising: a magnetic sheet in which said bubble domains exist, conductor means electrically contacting said sheet, there being a Schottky barrier tunnel junction formed between said sheet and at least one of said conductors, where the resistance of said tunnel junction depends upon the presence and absence of magnetic bubble domains in flux-coupling proximity thereto, means for providing domains in flux-coupling proximity to said tunnel junction, means for Providing electrical carriers through said tunnel junction, means for detecting the resistance of said tunnel junction indicating the presence and absence of magnetic bubble domains in flux-coupling proximity to said tunnel junction.
Claim 44
Dependent Claim
27 words
The apparatus of claim 39, where said means for providing domains is a propagation means located adjacent said magnetic sheet for moving domains in said magnetic sheet.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-07 | 1978-04-08 | 1978-10-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-07 | 1982-04-08 | 1982-10-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-07 | 1986-04-08 | 1986-10-08 | $7700.00 | Window Closed / Lapsed |