US4433034A
Expired / Lapsed
US
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Magnetic bubble layer of thulium-containing garnet
Assignee: Honeywell International Inc
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Filing: 1982-04-12
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Granted: 1984-02-21
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Expires: 2002-04-12
Abstract
Abstract Certain Tm-containing iron garnet compositions provide layers having desirably low values of temperature coefficient of bubble collapse field and permit the fabrication of 1.2 mu m diameter magnetic bubble devices. The compositions, based on Tm-substitution on dodecahedral sites of [(La,Bi),(Sm,Eu),R]3(Fe,Al,Ga)5O12, are grown by liquid phase epitaxy onto suitable substrates. Bubble devices that incorporate the layers find applications in high density information storage.
Inventors
- 👤 Devlin M. Gualtieri
- 👤 Paul F. Tumelty
- 👤 Mathias A. Gilleo, deceased
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 22:47
CPC Classifications
H; H01; H01F; H01F10/00; H01F10/08; H01F10/10; H01F10/18; H01F10/20; H01F10/24; Y; Y10; Y10S; Y10S428/00; Y10S428/90
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
154 words
A magnetic bubble domain device comprising an iron garnet layer that is capable of supporting magnetic bubble domains and that has a composition nominally represented by the formula: (La, Bi).sub.a (Sm, Eu).sub.b Tm.sub.c R.sub.3-a-b-c (Fe, Al, Ga).sub.5 O.sub.12 where R is at least one element of the group consisting of Y and the elements having atomic number from 57 to 71, a is from about 0.10 to about 0.18, b is from about 0.50 to about 0.70 and c is from about 0.8 to about 2.22; a magnet for maintaining in the layer a magnetic field that varies with temperature throughout a temperature range at an average variation rate; means adjacent to the layer for generating and moving the domains in the layer; and a gadolinium gallium garnet substrate for supporting the device, whereby a bubble collapse field of the layer varies with temperature throughout the temperature range at about the average variation rate.
Claim 2
Dependent Claim
154 words
A magnetic bubble domain device comprising an iron garnet layer that is capable of supporting magnetic bubble domains and that has a composition nominally represented by the formula: (La, Bi).sub.a (Sm, Eu).sub.b Tm.sub.c R.sub.3-a-b-c (Fe, Al, Ga).sub.5 O.sub.12 where R is at least one element of the group consisting of Y and the elements having atomic number from 57 to 71, a is from about 0.10 to about 0.18, b is from about 0.50 to about 0.70 and c is from about 0.8 to about 2.22; a magnet for maintaining in the layer a magnetic field that varies with temperature throughout a temperature range at an average variation rate; means adjacent to the layer for generating and moving the domains in the layer; and a gadolinium gallium garnet substrate for supporting the device, whereby a bubble collapse field of the layer varies with temperature throughout the temperature range at about the average variation rate.
Claim 3
Dependent Claim
22 words
The device of claim 1 in which R includes at least one element whose cationic size is smaller than that of Tm.
Claim 4
Dependent Claim
19 words
The device of claim 1 in which the composition is nominally represented by the formula Tm.sub.c (La,Sm,Lu).sub.3-c (Fe,Ga).sub.5 O.sub.12.
Claim 5
Dependent Claim
22 words
The device of claim 3 in which the composition is nominally represented by the formula La.sub.0.14 Sm.sub.0.60 Lu.sub.0.58 Tm.sub.1.52 Fe.sub.4.30 Ga.sub.0.60 O.sub.12.28.
Claim 6
Dependent Claim
12 words
The device of claim 1 in which the magnet is barium ferrite.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-02-20 | 1987-08-22 | 1988-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-20 | 1991-08-22 | 1992-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-20 | 1995-08-22 | 1996-02-21 | $7700.00 | Window Closed / Lapsed |