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US4468438A Expired / Lapsed US ⏱️ 0.0 years remaining

Garnet epitaxial films with high Curie temperatures

Assignee: Nokia Bell Labs
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Filing: 1981-12-07
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Granted: 1984-08-28
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Expires: 2001-12-07
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Abstract

Abstract The use of vanadium on the tetrahedral site of a garnet material together with a suitable charge compensating ion, such as Ca2+, results in advantageous materials. In particular, very high Curie temperatures, e.g., up to 524 degrees C., in films capable of supporting 1 mu m-sized bubble domains, are observed. Additionally, the change of collapse field with temperatures for magnetic bubble domains in the garnet material is linear and closely parallels over a wide temperature range the change of bubble controlling static field of permanent magnets typically employed in magnetic bubble devices. A substantially constant bubble size is maintainable over a wide temperature range. The desired garnet compositions are produced advantageously from a melt containing a suitable ratio of vanadium to calcium.

Inventors

  • 👤 Stuart L. Blank
  • 👤 Virendra V. S. Rana

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 04:43
CPC Classifications
H; H01; H01F; H01F41/00; H01F41/14; H01F41/24; H01F41/28; Y; Y10; Y10S; Y10S428/00; Y10S428/90

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 111 words
A process for growing a garnet film on a substrate comprising the steps of immersing said substrate in a growth melt, growing said film on said substrate, and removing said substrate from said melt characterized in that said process includes the step of producing said growth melt by forming a molten composition containing calcium and vanadium such that the mole ratio of said vanadium to said calcium is above 2.0, wherein said garnet film comprises a composition represented by the formula {RE 3-x Ca x }[M 5-y V y ]O 12 where y is in the range 0.50 to 0.65, where 0<x<3 and wherein said composition is essentially neutral in charge.
Claim 2
Dependent Claim 111 words
A process for growing a garnet film on a substrate comprising the steps of immersing said substrate in a growth melt, growing said film on said substrate, and removing said substrate from said melt characterized in that said process includes the step of producing said growth melt by forming a molten composition containing calcium and vanadium such that the mole ratio of said vanadium to said calcium is above 2.0, wherein said garnet film comprises a composition represented by the formula {RE 3-x Ca x }[M 5-y V y ]O 12 where y is in the range 0.50 to 0.65, where 0<x<3 and wherein said composition is essentially neutral in charge.
Claim 3
Dependent Claim 9 words
The process of claim 1 wherein M includes silicon.
Claim 4
Dependent Claim 13 words
The device of claim 2 wherein M consists essentially of iron and silicon.

References Cited (Backward Citations)

US4001793A Cited
US3964035A Cited
US4002803A Cited
US4034358A Cited
US4139905A Cited
US4337521A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1987-08-28 1988-02-27 1988-08-28 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1991-08-28 1992-02-27 1992-08-28 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1995-08-28 1996-02-27 1996-08-28 $7700.00 Window Closed / Lapsed

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