標題: | COPPER VALENCY OF SUPERCONDUCTING PHASES IN THE PB-DOPED BI-SR-CA-CU-O SYSTEM |
作者: | CHEN, FH KOO, HS WU, SC TSENG, TY HORNG, SR TAI, MF 電子工程學系及電子研究所 Department of Electronics Engineering and Institute of Electronics |
公開日期: | 1-七月-1992 |
摘要: | Pb-doped Bi-Sr-Ca-Cu high-T(c) superconducting oxides have been prepared by a modified sol-gel process via the EDTA route. Upon decomposing the X-ray photoemission spectrum of the Cu 2p3/2 core level of the superconducting oxide into three components Cu1+, Cu2+ and Cu3+, we have found an obvious trend: the corresponding [Cu1+]/[Cu2+] ratio increased as more 110 K phase was formed in the sample. According to this trend, a defect model was proposed; it can reasonably explain some previous experimental results, such as a reduced oxygen atmosphere sintering, which effectively facilitates the formation of the 110 K phase, and the coexistence of copper and oxygen vacancies in Bi-system superconductors, observed by high-resolution transmission electron microscopy. On the other hand, the dimerization of holes in oxygen sites was also suggested to be a possible mechanism responsible for the increase in the ratio of [Cu1+]/[Cu2+]. |
URI: | http://hdl.handle.net/11536/3367 |
ISSN: | 0921-4534 |
期刊: | PHYSICA C |
Volume: | 197 |
Issue: | 1-2 |
起始頁: | 151 |
結束頁: | 156 |
顯示於類別: | 期刊論文 |