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Oxygen-Diffusion and Structural Modification in Air-Annealed Superconducting Bi2Sr2CaCu2Oy Single Crystals |
| ZHAO Xiao-ru1,3;WU Wen-bin1;SUN Xue-feng1;WANG Liang-bin1;ZHOU Gui-en1;LI Xiao-Guang1;ZHANG Yu-heng1,2;Koichi Kitazawa3 |
| 1Structure Research Laboratory, University of Science and Technology of China, Hefei 230026
2CCAST (World Laboratory), P.O. Box 8730, Beijing 100080
3Department of Applied Chemistry, Department of Superconductivity, University of Tokyo, 7-3-1 Hongo, Bunkyo 113, Japan
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| Cite this article: |
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ZHAO Xiao-ru, WU Wen-bin, SUN Xue-feng et al 1997 Chin. Phys. Lett. 14 936-939 |
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Abstract Bi2Sr2CaCu2Oy single crystals were air-annealed at 300, 400, 600 and 750°C for 20h in consequence. Measurements of ac susceptibility and x-ray diffraction showed that at annealing temperature below 400°C, the change of Tc was dominated by oxygen-diffusion involved in pervoskite unit and was strongly sample-dependent. This diffusion from pervoskite unit occurred earlier than that from Bi-O layers. At annealing temperature over 400°C, with the intercalation of excess oxygen into Bi-O layers, the hole concentration in the crystal was redistributed so that Bi-O reservoir fully determined superconductivity. From the changes of non-uniform strain in annealing process, it was found that structural modification was also closely correlated to superconductivity.
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74.60.-w
66.30.-h
61.10.-i
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Published: 01 December 1997
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