Claims
- 1. A method of fabricating bulk YBa.sub.2 Cu.sub.3 O.sub.x comprising heating compressed powder oxides and/or carbonates of Y and Ba and Cu present in mole ratios to form YBa.sub.2 Cu.sub.3 O.sub.x in the presence of a Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y seed crystal to a temperature sufficient to form a liquid phase in the YBa.sub.2 Cu.sub.3 O.sub.x while maintaining the seed crystal solid and thereafter cooling to provide a YBa.sub.2 Cu.sub.3 O.sub.x material having a predetermined number of domains between 1 and 5.
- 2. The method of claim 1, wherein the heating and/or the cooling includes providing a temperature gradient of up to about 30.degree. c./cm parallel to a longitudinal axis of the YBa.sub.2 Cu.sub.3 O.sub.x material.
- 3. The method of claim 2, wherein the bulk YBa.sub.2 Cu.sub.3 O.sub.x has up to 25% by weight YBa.sub.2 Cu.sub.3 O.sub.x and up to about 1% by weight PtO.sub.2.
- 4. The method of claim 3, wherein the seed crystal is cube shaped.
- 5. The method of claim 3, wherein the seed crystal is plate shaped.
- 6. The method of claim 3, wherein the compressed powder is heated to a temperature not greater than about 1070.degree. C.
- 7. A method of fabricating crack-free single-domain YBa.sub.2 Cu.sub.3 O.sub.x materials, comprising interposing a preferential growth material between and in contact with powders of the oxides and/or carbonates of Y, Ba and Cu present in mole ratios to form YBa.sub.2 Cu.sub.3 O.sub.x and a cube-shaped seed crystal essentially of Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y, heating to a temperature sufficient to form a liquid phase in the YBa.sub.2 Cu.sub.3 O.sub.x material while maintaining the Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y seed crystal solid, and thereafter cooling to produce a crack-free single-domain YBa.sub.2 Cu.sub.3 O.sub.x material.
- 8. The method of claim 7, wherein the seed crystal is solely Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y.
- 9. The method of claim 7, wherein the bulk YBa.sub.2 Cu.sub.3 O.sub.x is doped with PtO.sub.2.
- 10. The method of claim 7, wherein the bulk YBa.sub.2 Cu.sub.3 O.sub.x prior to heating includes up to about 25% by weight of Y.sub.2 BaCuO.sub.x and up to about 1% by weight PtO.sub.2 and is unsintered.
- 11. The method of claim 7, wherein the preferential growth material is generally cylindrical and includes YBa.sub.2 Cu.sub.3 O.sub.x.
- 12. The method of claim 10, wherein the seed crystal is cube-shaped Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y smaller than the transverse cross-sectional area of the preferential growth material, the preferential growth material having a longitudinal extent sufficient to ensure a single domain in the bulk YBa.sub.2 Cu.sub.3 O.sub.x.
- 13. The method of claim 10, wherein the seed crystal is Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y larger than the cross-sectional area of the preferential growth material, the preferential growth material cylinder having a longitudinal extant sufficient to ensure a single domain in the YBa.sub.2 Cu.sub.3 O.sub.x.
- 14. The method of claim 7, wherein a temperature gradient in the range of from 10.degree. C./cm to about 30.degree. C./cm is applied to a longitudinal axis of the YBa.sub.2 Cu.sub.3 O.sub.x during heating and/or cooling.
- 15. The method of claim 7, wherein a temperature gradient of up to 30.degree. C./cm is applied to the YBa.sub.2 Cu.sub.3 O.sub.x material during heating and/or cooling in a direction parallel to the C-axis.
- 16. A method of fabricating crack-free single domain YBa.sub.2 Cu.sub.3 O.sub.x material, comprising contacting powders of the oxides and/or carbonates of Y, Ba and Cu present in mole ratios to form YBa.sub.2 Cu.sub.3 O.sub.x with a plate-shaped Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y seed crystal, heating to a temperature sufficient to form a liquid phase in the YBa.sub.2 Cu.sub.3 Ox material while maintaining the Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y seed crystal solid, and thereafter cooling to produce a crack-free single-domain YBa.sub.2 Cu.sub.3 O.sub.x material.
- 17. The method of claim 16, wherein the single domain material includes up to about 25% by weight YBa.sub.2 Cu.sub.3 O.sub.x and up to about 1% by weight PtO.sub.2.
- 18. A method of fabricating multiple domain YBa.sub.2 Cu.sub.3 O.sub.x materials, comprising contacting a cube-shaped Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y seed crystal with compressed powders of the oxides and/or carbonates of Y, Ba and Cu present in mole ratios to form YBa.sub.2 Cu.sub.3 O.sub.x material, heating to a temperature sufficient to form a liquid phase in the YBa.sub.2 Cu.sub.3 O.sub.x material while maintaining the seed crystals solid, and thereafter cooling to produce a multiple domain YBa.sub.2 Cu.sub.3 O.sub.x material.
- 19. The method of claim 18, wherein the material has up to 5 domains.
- 20. The method of claim 19, wherein the multiple domain YBa.sub.2 Cu.sub.3 O.sub.x material contains up to 25% by weight Y.sub.2 BaCuO.sub.x and up to about 1% by weight PtO.sub.2.
- 21. The method of claim 20, wherein a temperature gradient is applied during heating and/or cooling in the range of from 10.degree. C./cm to about 30.degree. C./cm along a longitudinal axis of the YBa.sub.2 Cu.sub.3 O.sub.x material.
- 22. A method of fabricating crack-free single-domain YBa.sub.2 Cu.sub.3 O.sub.x materials, comprising interposing a preferential growth material between and in contact with powders of the oxides and/or carbonates of Y, Ba and Cu present in mole ratios to form YBa.sub.2 Cu.sub.3 O.sub.x and a cube-shaped seed crystal essentially of RE.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y, heating to a temperature sufficient to form a liquid phase in the YBa.sub.2 Cu.sub.3 O.sub.x material while maintaining the RE.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y seed crystal solid, and thereafter cooling to produce a crack-free single-domain YBa.sub.2 Cu.sub.3 O.sub.x material, wherein RE of the seed crystal is Nd or a mixture of Nd and Sm.
Parent Case Info
This is a continuation of application Ser. No. 08/371,931, filed Jan. 12, 1995 now ABN.
CONTRACTUAL ORIGIN OF THE INVENTION
The United States Government has rights in this invention pursuant to Contract No. W-31-109-ENG-38 between the U.S. Department of Energy and The University of Chicago representing Argonne National Laboratory.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
Country |
5-170598 |
Jul 1993 |
JPX |
Non-Patent Literature Citations (3)
Entry |
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Superconductivity of YBa.sub.2 Cu.sub.3 O.sub.7x by Addition of Reactive Fine Powders, Vo.30 No. 2. Feb. 1991, pp. 245-250, Sakai et al. J.J.A.P. |
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Continuations (1)
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Number |
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Parent |
371931 |
Jan 1995 |
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