US6233172B1
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Magnetic element with dual magnetic states and fabrication method thereof
Assignee: Everspin Technologies Inc
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Filing: 1999-12-17
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Granted: 2001-05-15
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Expires: 2019-12-17
Abstract
Abstract An improved and novel magnetic element ( 10; 10′; 50; 50′; 80 ) including a plurality of thin film layers wherein the bit end magneto-static demagnetizing fields cancel the total positive coupling of the structure to obtain dual magnetic states in a zero external field. Additionally disclosed is a method of fabricating a magnetic element ( 10 ) by providing a plurality of thin film layers wherein the bit end magneto-static demagnetizing fields of the thin film layers cancel the total positive coupling of the structure to obtain dual magnetic states in a zero external field.
Inventors
- 👤 Eugene Youjun Chen
- 👤 Jon Michael Slaughter
- 👤 Mark Durlam
- 👤 Mark DeHerrera
- 👤 Saied N. Tehrani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 16:53
CPC Classifications
H; H10; H10N; H10N50/00; H10N50/10; H01; H01F; H01F10/00; H01F10/32; H01F10/324; H01F10/3254; B; B82; B82Y; B82Y25/00; G; G11; G11C; G11C11/00; G11C11/02; G11C11/16; G11C11/161; H01F10/3268; H01F10/3272
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
38 words
A magnetic element comprising a plurality of thin film layers wherein a plurality of bit end magneto-static demagnetization fields cancel the total positive coupling of the magnetic element to obtain dual magnetic states in a zero external field.
Claim 2
Dependent Claim
38 words
A magnetic element comprising a plurality of thin film layers wherein a plurality of bit end magneto-static demagnetization fields cancel the total positive coupling of the magnetic element to obtain dual magnetic states in a zero external field.
Claim 3
Dependent Claim
29 words
A magnetic element as claimed in claim 1 wherein the plurality of thin film layers form one of a spin valve structure or a magnetic tunnel junction (MTJ) structure.
Claim 4
Dependent Claim
56 words
A magnetic element as claimed in claim 2 wherein the plurality of thin film layers form a SAF structure having a fixed ferromagnetic layer and a pinned ferromagnetic layer, the fixed ferromagnetic layer having a thickness greater than the pinned ferromagnetic layer thereby canceling positive coupling between the fixed ferromagnetic layer and a free ferromagnetic layer.
Claim 5
Dependent Claim
55 words
A magnetic element as claimed in claim 2 wherein the plurality of thin film layers form a structure including a plurality of ferromagnetic layers having differing switching fields, wherein an offset between the ferromagnetic layers provides for a decrease in the demagnetizing field between the ferromagnetic layers thereby canceling positive coupling between the ferromagnetic layers.
Claim 6
Dependent Claim
59 words
A magnetic element as claimed in claim 4 wherein the plurality of ferromagnetic layers include a pinned ferromagnetic layer and a free ferromagnetic layer, and the offset provides for a decrease in the demagnetizing field from the pinned ferromagnetic layer to the free ferromagnetic layer thereby canceling positive coupling between the pinned ferromagnetic layer and the free ferromagnetic layer.
Claim 7
Dependent Claim
80 words
A magnetic element as claimed in claim 2 wherein the plurality of thin film layers form a structure including a free ferromagnetic layer, a plurality of spacer layers, and a plurality of ferromagnetic layers having antiparallel alignment due to end-magneto static coupling, wherein the thickness of at least one of the plurality of ferromagnetic layers is adjusted to provide for the canceling of positive coupling between the free ferromagnetic layer and at least one of the plurality of ferromagnetic layers.
Claim 8
Dependent Claim
171 words
A magnetic element comprising: a first electrode comprising a fixed ferromagnetic layer whose magnetization is fixed in a preferred direction in the presence of an applied magnetic field having a specific strength, the fixed ferromagnetic layer having a thickness 1 (t 1 ), a pinned ferromagnetic layer having a thickness 2 (t 2 ) and a coupling interlayer located between the fixed ferromagnetic layer and the pinned ferromagnetic layer; a second electrode comprising a free ferromagnetic layer having a surface whose magnetization is free to rotate in the presence of a sufficient applied magnetic field; a spacer layer located between the fixed ferromagnetic layer of the first electrode and the free ferromagnetic layer of the second electrode; wherein the thickness t 1 , of the fixed ferromagnetic layer is greater than the thickness t 2 of the pinned ferromagnetic layer thereby canceling positive coupling between the fixed ferromagnetic layer and the free ferromagnetic layer; and a substrate, the first and second electrodes, and the spacer layer, being formed on the substrate.
Claim 9
Dependent Claim
171 words
A magnetic element comprising: a first electrode comprising a fixed ferromagnetic layer whose magnetization is fixed in a preferred direction in the presence of an applied magnetic field having a specific strength, the fixed ferromagnetic layer having a thickness 1 (t 1 ), a pinned ferromagnetic layer having a thickness 2 (t 2 ) and a coupling interlayer located between the fixed ferromagnetic layer and the pinned ferromagnetic layer; a second electrode comprising a free ferromagnetic layer having a surface whose magnetization is free to rotate in the presence of a sufficient applied magnetic field; a spacer layer located between the fixed ferromagnetic layer of the first electrode and the free ferromagnetic layer of the second electrode; wherein the thickness t 1 , of the fixed ferromagnetic layer is greater than the thickness t 2 of the pinned ferromagnetic layer thereby canceling positive coupling between the fixed ferromagnetic layer and the free ferromagnetic layer; and a substrate, the first and second electrodes, and the spacer layer, being formed on the substrate.
Claim 10
Dependent Claim
50 words
A magnetic element as claimed in claim 7 wherein the pinned ferromagnetic layer has its magnetization fixed by an antiferromagnetic pinning layer, and the fixed ferromagnetic layer is fixed in the opposite direction by antiferromagnetic exchange to the pinned ferromagnetic layer through a coupling interlayer, thereby defining a SAF structure.
Claim 11
Dependent Claim
17 words
A magnetic element as claimed in claim 7 wherein the coupling interlayer is formed of ruthenium (Ru).
Claim 12
Dependent Claim
23 words
A magnetic element as claimed in claim 7 further including at least one offset between the free ferromagnetic layer and the spacer layer.
Claim 13
Dependent Claim
31 words
A magnetic element as claimed in claim 7 wherein the spacer layer includes one of a dielectric material defining a MTJ structure or a conductive material defining a spin valve structure.
Claim 14
Dependent Claim
135 words
A magnetic element comprising: a first electrode comprising a pinned ferromagnetic layer whose magnetic moment is pinned in a preferred direction in the presence of an applied magnetic field characterized as having a specific strength; a second electrode comprising a free ferromagnetic layer having a surface whose magnetization is free to rotate in the presence of a sufficient applied magnetic field; a spacer layer located between the pinned ferromagnetic layer of the first electrode and the free ferromagnetic layer of the second electrode; wherein an offset provides for a decrease in the demagnetizing field from the pinned ferromagnetic layer to the free ferromagnetic layer thereby canceling positive coupling between the pinned ferromagnetic layer and the free ferromagnetic layer; and a substrate, the first and second electrodes, and the spacer layer, being formed on the substrate.
Claim 15
Dependent Claim
135 words
A magnetic element comprising: a first electrode comprising a pinned ferromagnetic layer whose magnetic moment is pinned in a preferred direction in the presence of an applied magnetic field characterized as having a specific strength; a second electrode comprising a free ferromagnetic layer having a surface whose magnetization is free to rotate in the presence of a sufficient applied magnetic field; a spacer layer located between the pinned ferromagnetic layer of the first electrode and the free ferromagnetic layer of the second electrode; wherein an offset provides for a decrease in the demagnetizing field from the pinned ferromagnetic layer to the free ferromagnetic layer thereby canceling positive coupling between the pinned ferromagnetic layer and the free ferromagnetic layer; and a substrate, the first and second electrodes, and the spacer layer, being formed on the substrate.
Claim 16
Dependent Claim
31 words
A magnetic element as claimed in claim 12 wherein the spacer layer includes one of a dielectric material defining a MTJ structure or a conductive material defining a spin valve structure.
Claim 17
Independent Claim
46 words
A method of fabricating a magnetic element comprising the step of providing a plurality of thin film layers wherein a plurality of bit end magneto-static demagnetizing fields cancel the total positive coupling of the magnetic element to obtain dual magnetic states in a zero external field.
Claim 18
Independent Claim
46 words
A method of fabricating a magnetic element comprising the step of providing a plurality of thin film layers wherein a plurality of bit end magneto-static demagnetizing fields cancel the total positive coupling of the magnetic element to obtain dual magnetic states in a zero external field.
Claim 19
Dependent Claim
49 words
A method of fabricating a magnetic element as claimed in claim 14 wherein the step of providing a plurality of thin film layers includes the step of providing the plurality of thin film layers to form one of a spin valve structure or a magnetic tunnel junction (MTJ) structure.
Claim 20
Dependent Claim
68 words
A method of fabricating a magnetic element as claimed in claim 15 wherein the step of providing a plurality of thin film layers includes the step of forming a SAF structure having a fixed ferromagnetic layer and a pinned ferromagnetic layer, the fixed ferromagnetic layer having a thickness greater than the pinned ferromagnetic layer thereby canceling positive coupling between the fixed ferromagnetic layer and a free ferromagnetic layer.
Claim 21
Dependent Claim
67 words
A method of fabricating a magnetic element as claimed in claim 15 wherein the step of providing a plurality of thin film layers includes the step of forming a structure including a plurality of ferromagnetic layers having differing switching fields, wherein an offset between the ferromagnetic layers provides for a decrease in the demagnetizing field between the ferromagnetic layers thereby canceling positive coupling between the ferromagnetic layers.
Claim 22
Dependent Claim
67 words
A magnetic element as claimed in claim 17 wherein the step of providing a plurality of ferromagnetic layers includes the step of forming a pinned ferromagnetic layer and a free ferromagnetic layer, and the offset provides for a decrease in the demagnetizing field from the pinned ferromagnetic layer to the free ferromagnetic layer thereby canceling positive coupling between the pinned ferromagnetic layer and the free ferromagnetic layer.
Claim 23
Dependent Claim
92 words
A method of fabricating a magnetic element as claimed in claim 15 wherein the step of providing a plurality of thin film layers includes the step of forming a structure including a free ferromagnetic layer, a plurality of spacer layers, and a plurality of ferromagnetic layers having antiparallel alignment due to end-magneto static coupling, wherein the thickness of at least one of the plurality of ferromagnetic layers is adjusted to provide for the canceling of positive coupling between the free ferromagnetic layer and at least one of the plurality of ferromagnetic layers.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-05-14 | 2004-11-13 | 2005-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-05-14 | 2008-11-13 | 2009-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-05-14 | 2012-11-13 | 2013-05-15 | $7700.00 | Window Closed / Lapsed |