Claims
- 1. A method for preparing a superconductive thin film comprising the steps of:
- preparing a target from the oxides of Ba, Y, and Cu in atomic ratio of Cu/Y of 2.5 to 3.5 and Ba/Y of 1.8 to 2.2;
- sputtering said target to form a superconducting thin film on a substrate at a temperature of 650.degree. to 750.degree. C., said sputtering step being carried out in an atmosphere having a total gas pressure of 1.times.10.sup.-1, to 5.times.10.sup.-2 Torr and containing Ar and O.sub.2 content with an O.sub.2 content of 16 to 80 vol. %;
- performing a heat treatment at 600.degree. to 800.degree. C. of said thin film thus formed; and
- cooling said thin film after said heat treatment at a rate of up to 4.degree. C./min.
- 2. A method in accordance with claim 1, wherein said heat treatment is performed for 1 to 30 hours.
- 3. A method in accordance with claim 1, wherein said heat treatment is performed for 10 to 30 hours.
- 4. A method in accordance with claim 1 wherein said sputtering is performed in an atmosphere containing Ar and O.sub.2 with an O.sub.2 context of 16 to 50 vol. %.
- 5. A method in accordance with claim 1, wherein said substrate is selected from the group of MgO, SrTiO.sub.3, Al.sub.2 O.sub.3, sapphire, SiO.sub.2, quartz, YSZ, and ZnO.
- 6. A method in accordance with claim 1, wherein said substrate is MgO or SrTiO.sub.3.
- 7. A method in accordance with claim 1, wherein said superconducting thin film is formed on the (110) surface of a single crystal substrate of MgO or SrTiO.sub.3.
- 8. A method in accordance with claim 1, wherein said superconducting thin film is formed on the (110) surface of a single crystal substrate of MgO or SrTiO.sub.3.
- 9. A method in accordance with claim 1, wherein the distance between said target and said substrate is 20 to 45 mm.
- 10. A method in accordance with claim 1, wherein a superconducting thin film of Y-Ba-Cu-O is formed.
- 11. A method in accordance with claim 1, wherein a superconducting thin film of composition Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-n is formed, where n represents a number in the range of 0.ltoreq.n<1.
- 12. A method in accordance with claim 1, wherein a superconducting thin film of an oxide having perovskite or pseudo-perovskite crystal structure is formed.
- 13. A method in accordance with claim 1, wherein said heat treatment is performed in an atmosphere containing O.sub.2.
- 14. A method in accordance with claim 1, wherein said superconductive thin film is formed by magnetron sputtering.
- 15. A method of preparing a superconducting thin film comprising the steps of:
- preparing a target from oxides of Ba, Y, and Cu in atomic ratios of Cu/Y of 2.5 to 3.5 and Ba/Y of 1.8 to 2.2;
- sputtering said superconducting thin film of the material of said target onto the (100) surface of a single heated crystal substrate which is lattice-matched with the (100) surface of crystalline Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-n, wherein n represents a number of the range 0.ltoreq.n.ltoreq.1, said sputtering being carried out in an atmosphere having a total gas pressure of 1.times.10.sup.-2 to 5.times.10.sup.-2 Torr and containing Ar and O.sub.2 with an O.sub.2 content of 16 to 80 vol. %;
- heat treating at 600.degree. to 800.degree. C. the thin film thus formed; and
- cooling said thin film after said heat treatment step at a rate of up to 4.degree. C./min.
- 16. A method in accordance with claim 15, wherein the (100) surface of said single crystal substrate has a lattice constant approximately that of the a-axis or b-axis of the (100) surface of crystalline Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-n, where n represents a number in the range 0.ltoreq.n<1.
- 17. A method in accordance with claim 15, wherein said substrate is MgO.
- 18. A method in accordance with claim 15, wherein the distance between said target and said substrate is 20 to 45 mm.
- 19. A method in accordance with claim 15, wherein said heat treatment is performed for 10 to 30 hours.
- 20. A method in accordance with claim 15, wherein said sputtering is performed in an atmosphere containing Ar and O.sub.2 with an O.sub.2 content of 16 to 50 vol. %.
- 21. A method in accordance with claim 15, forming a superconducting thin film of Y-Ba-Cu-O.
- 22. A method in accordance with claim 15, wherein a superconducting thin film of composition Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-n is formed, where n represents a number in the range 0.ltoreq.n<1.
- 23. A method in accordance with claim 15, wherein a superconducting thin film of an oxide having perovskite or pseudo-perovskite crystal structure is formed.
- 24. A method in accordance with claim 15, wherein said heat treatment is performed in an atmosphere containing O.sub.2.
- 25. A method in accordance with claim 15, wherein said superconducting thin film is formed by magnetron sputtering.
Priority Claims (3)
Number |
Date |
Country |
Kind |
62-136938 |
May 1987 |
JPX |
|
62-140610 |
Jun 1987 |
JPX |
|
62-140612 |
Jun 1987 |
JPX |
|
Parent Case Info
This is a continuation of application Ser. No. 07/649,121 filed Jan. 28, 1991, now abandoned, which is a continuation of application Ser. No. 07/463,908, filed Jan. 10, 1990, now abandoned, which is a continuation of application Ser. No. 07/200,275, filed May 31, 1988, now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5057201 |
Fujita et al. |
Oct 1991 |
|
Non-Patent Literature Citations (5)
Entry |
H. Adachi et al, Jap. J. Appl. Phys., vol. 26, May 1987, pp. L709-L710. |
H. Koinuma et al, Jap. J. Appl. Phys., vol. 26, May 1987, pp. L763-L765. |
Y. Enomoto et al, Jap. J. Appl. Phys., vol. 26, Jul. 1987, pp. L1248-L1250. |
H. Ohkuma et al, Jap. J. Appl. Phys., vol. 26, Sep. 1987, pp. L1484-L1486. |
T. Aida et al., Jap. J. Appl. Phys., vol. 26, Sep. 1987, pp. L1489-L1491. |
Continuations (3)
|
Number |
Date |
Country |
Parent |
649121 |
Jan 1991 |
|
Parent |
463908 |
Jan 1990 |
|
Parent |
200275 |
May 1988 |
|