Claims
- 1. An electronic device comprising:
(a) a crystalline substrate; (b) an electrode formed on and epitaxial to the substrate, the electrode comprising a first superconductive oxide; (c) an insulator formed on and epitaxial to the electrode; (d) a barrier comprising an ion-treated surface of the first superconductive oxide; and (e) a counter-electrode formed on and epitaxial to the electrode and the barrier, the counter-electrode comprising a second superconductive oxide, whereby a Josephson junction is formed between the electrode and the counter-electrode.
- 2. The device of claim 1, wherein the barrier is a surface formed by treating the first superconductive oxide with a plasma comprising a gas selected from the group consisting of argon, xenon, oxygen, and halogen.
- 3. The device of claim 2, wherein the gas is argon gas.
- 4. The device of claim 2, wherein the gas is a 1:1 mixture of argon and oxygen.
- 5. The device of claim 1 wherein the first superconductive oxide has an a-b plane and a step-edge junction is formed in the a-b plane of the first superconductive oxide.
- 6. The device of claim 1 wherein the first superconductive oxide has an a-b plane, the a-b plane is epitaxial to the substrate, and the second superconductive oxide is on and epitaxial to the first superconductive element, whereby a junction is formed perpendicular to the a-b plane of the first superconductive oxide.
- 7. The device of any one of claims 1-6, wherein the first and second superconductive oxide is YBCO.
- 8. The device of claim 1, the device having an IcRn value of at least about 0.3 mV at a temperature of 4.2 K.
- 9. The device of claim 2, the device having an IcRn value of at least about 0.3 mV at a temperature of 4.2 K.
- 10. The device of claim 3, the device having an IcRn value of at least about 0.3 mV at a temperature of 4.2 K.
- 11. The device of claim 4, the device having an IcRn value of at least about 0.3 mV at a temperature of 4.2 K.
- 12. The device of claim 5, the device having an IcRn value of at least about 0.3 mV at a temperature of 4.2 K.
- 13. The device of claim 6, the device having an IcRn value of at least about 0.3 mV at a temperature of 4.2 K.
- 14. The device of claim 7, the device having an IcRn value of at least about 0.3 mV at a temperature of 4.2 K.
- 15. The device of claim 1, the device having an IcRn value of at least about 0.5 mV at a temperature of 40 K.
- 16. The device of claim 2, the device having an IcRn value of at least about 0.5 mV at a temperature of 40 K.
- 17. The device of claim 3, the device having an IcRn value of at least about 0.5 mV at a temperature of 40 K.
- 18. The device of claim 4, the device having an IcRn value of at least about 0.5 mV at a temperature of 40 K.
- 19. The device of claim 5, the device having an IcRn value of at least about 0.5 mV at a temperature of 40 K.
- 20. The device of claim 6, the device having an IcRn value of at least about 0.5 mV at a temperature of 40 K.
- 21. The device of claim 7, the device having an IcRn value of at least about 0.5 mV at a temperature of 40 K.
- 22. A process for making a Josephson junction device comprising the steps of:
(a) preparing a substrate; (b) depositing an electrode comprising a first layer of a superconductive oxide on the substrate; (c) depositing an insulating layer on the first layer of superconductive oxide; (d) patterning to form a pre-device having an exposed surface of the first superconductive oxide; (e) placing the pre-device into a deposition chamber; (f) forming a barrier on the exposed surface of the first layer of superconductive oxide by treating the exposed surface with ions; and (g) depositing a second layer of a superconductive oxide on the pre-device, whereby a Josephson junction is formed between the first and the second superconductive oxides at the barrier.
- 23. The process of claim 22, wherein the treating with ions is accomplished with a plasma of Ar gas at a pressure of between 10 and 100 mTorr.
- 24. The process of claim 22, wherein the treating with ions is with a mixture of Ar and O2 gas at a pressure of between 10 and 100 mTorr.
- 25. The process of any one of claims 22-24, further comprising the step of vacuum annealing the pre-device prior to depositing the second superconductive oxide.
- 26. A superconductor device, comprising:
a) an oxide superconductor having a surface exposed to ambient environment; and b) a passivation layer covering at least a portion of the surface of the oxide superconductor that is exposed to the ambient environment.
- 27. The device claim 26, further comprising a buffer layer at least partially between the passivation layer and the oxide superconductor.
- 28. The device of claim 26, wherein the passivation layer originates from the superconductor.
- 29. The device of claim 28, wherein the passivation layer is an ion-modified layer of the superconductor.
- 30. The device of claim 26, wherein the oxide superconductor comprises YBa2Cu3O7-δ, wherein δ≧0.
- 31. The device of claim 26, wherein the passivation layer is an electrical insulator.
- 32. The device of claim 26, wherein the passivation layer is epitaxial and crystalline.
- 33. The device of claim 26, wherein the passivation layer covers the entire surface of the oxide superconductor that is exposed to the ambient environment.
- 34. The device of claim 26, further comprising a layer of a superconductive oxide on the passivation layer, whereby a Josephson junction is formed between the superconductive oxides.
- 35. A method of providing a passivation layer on the surface of an oxide superconductor, the method comprising vacuum annealing and ion treating at least a portion of the surface of the oxide superconductor that is exposed to ambient environment.
- 36. The method of claim 35, further comprising additional vacuum annealing after the ion treatment.
- 37. The method of claim 35, further comprising heating in an oxygen-rich environment after the ion treatment.
- 38. The method of claim 35, comprising vacuum annealing and ion treating the entire surface of the oxide superconductor that is exposed to ambient environment
- 39. A method of making a superconductor device, the method comprising:
a) forming a layer of oxide superconductor on a substrate, the layer of oxide superconductor having a surface that is exposed to ambient environment; and b) passivating at least a portion of the surface of the oxide superconductor that is exposed to ambient environment.
- 40. The method of claim 39, comprising passivating the entire exposed surface of the oxide superconductor.
- 41. The method of claim 39, wherein the passivating step comprises bombarding the exposed surface portion with ions.
- 42. The method of claim 41, further comprising annealing the layer of oxide superconductor between steps (a) and (b).
- 43. The method of claim 42, further comprising annealing the layer of oxide superconductor after step (b).
- 44. The method of claim 42, wherein the bombarding step comprises treating the exposed surface portion with plasma.
- 45. The method of claim 39, wherein step (a) comprises forming a layer of YBa2Cu3O7-δ, wherein δ≧0.
- 46. The method of claim 42, further comprising heating the oxide superconductor in oxygen after step (b).
- 47. The method of claim 46, further comprising cooling the oxide superconductor to room temperature in oxygen after heating the oxide superconductor in oxygen.
- 48. The method of claim 41, further comprising maintaining the layer of oxide superconductor at a temperature of between about 300° C. and about 650° C. while bombarding the exposed surface portion with ions.
- 49. The method of claim 46, wherein the heating step comprises maintaining the layer of oxide superconductor at a temperature of between about 700° C. and about 800° C. after treating the exposed surface portion with plasma.
- 50. The method of claim 39, wherein the passivation step comprises changing a surface layer of the oxide superconductor to a material different from the oxide superconductor.
- 51. The method of claim 50, wherein the changing step comprises changing the surface layer of the oxide superconductor to a material having an oxygen mobility that is lower than the oxygen mobility in the oxide superconductor.
- 52. The method of claim 39, further comprising forming a layer of oxide superconductor on at least a portion of the passivated surface portion, whereby a Josephson junction is formed between the oxide superconductors.
- 53. A passivation layer comprising an ion-modified layer on an oxide superconductor, the ion-modified layer covering at least a portion of the surface of the oxide superconductor that would otherwise be exposed to ambient environment, and the ion-modified layer having an oxygen mobility that is lower than an oxygen mobility of the oxide superconductor.
- 54. The passivation layer of claim 53, wherein the ion-modified layer is formed by material originating from the oxide superconductor.
- 55. The passivation layer of claim 53, wherein the ion-modified layer is an externally applied layer that is bonded to the oxide superconductor.
- 56. The passivation layer of claim 55, wherein the ion-modified layer is quasi-cubic and is not YBa2Cu3O7-δ, wherein δ≧0.
- 57. The passivation layer of claim 53, wherein the ion-modified layer is epitaxial and crystalline.
- 58. The passivation layer of claim 53, the ion-modified layer covering the entire surface of the oxide superconductor that would otherwise be exposed to ambient environment
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation-in-part of U.S. patent application Ser. No. 10/704,215, filed Nov. 6, 2003, which is a continuation of U.S. patent application Ser. No. 09/082,486, filed May 20, 1998, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/047,555, filed May 22, 1997; and claims the benefit of U.S. Provisional Patent Application Ser. No. 60/437,781, which applications are hereby incorporated by reference in their entirety.
STATEMENT OF GOVERNMENT INTEREST
[0002] This invention was made with United States Government support under Contract No. N0014-96-C-2095 awarded by the Naval Research Laboratory. The United States Government has certain rights in the invention.
Provisional Applications (2)
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Number |
Date |
Country |
|
60047555 |
May 1997 |
US |
|
60437781 |
Jan 2003 |
US |
Continuations (1)
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Number |
Date |
Country |
Parent |
09082486 |
May 1998 |
US |
Child |
10704215 |
Nov 2003 |
US |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
10704215 |
Nov 2003 |
US |
Child |
10751091 |
Jan 2004 |
US |