HIGH-Tc SUPERCONDUCTING PROPERTIES OF YBa2Cu3-xSnx O7-y SYSTEM
WANG Yuxia, RUAN Yaozhong, TAN Yudong, WANG Xiaozhong, ZHOU Guien*, FAN Chenggao*, ZHANG Yuheng*
Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026
Structure and Components Alalysu Center, University of Science and Technology of China, Heifei 230026
HIGH-Tc SUPERCONDUCTING PROPERTIES OF YBa2Cu3-xSnx O7-y SYSTEM
WANG Yuxia;RUAN Yaozhong;TAN Yudong;WANG Xiaozhong;ZHOU Guien*;FAN Chenggao*;ZHANG Yuheng*
Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026
Structure and Components Alalysu Center, University of Science and Technology of China, Heifei 230026
Abstract： The effect of Sn concentration on the superconducting properties and structure of YBa2Cu3-xSnx O7-y system were systematically investigated. The zero resistance temperature was found to be above 90K as z ranges from 0 to 1.1. For x > 1.3, the system exhibited no superconducting properties at liquid nitrogen temperature. The results of X-ray diffraction showed a regular pattern of mixed structures of 123 phase and a new phase in the system with the increase of Sn concentration. TEM analysis suggested that the new phase might be BaSnO3 with deformed perovskite structure and about 6% of Cu were substituted by Sn in the 123 phase at x = 1.0. It is therefore likely that the new phase modulates the structure of 123 phase and stabilize the 123 phase. Although the Sn atoms enter 123 phase and occupy the Cu sites in the Cu-O chain and break the chain, the system remains with Tc > 90K. Consequently, the Cu-O chain plays a less important role in the high-Tc superconductivity.
1990, Vol. 7 
