High Critical Temperature Oxide Superconductors Preparation And Performance

Superconductors are materials which have zero resistence and Messiner effect when they are in low temperature. They are called low temperature superconductor if their critical temperature below 40K, and if their critical temperature are higher than 40K, they are called high-temperature-superconductors (HTS). The critical temperature of YBCO superconductor is about 90K. The critical temperature of the YBCO superconductor is about 90K. It is studied frequently because of its high critical temperature and excellent superconducting properties. BSCCO superconductor is also a promising superconductor. Its critical temperature is about 110K. BSCCO superconductor is widely used in preparing superconducting block and superconducting strap. YBCO superconductor and BSCCO superconductor are prepared in this paper. The effect of ZnO doping on the BSCCO superconductor is studied. In order to measure the Tc of the superconductors, we put up a superconductor measuring system.Firstly, we prepared YBCO superconductor pre-sinter powders by dry method and Sol-gel method. XRD and Tc measuring are used to analyzed the sample. The Tc value of the sample is about 88K, the sample has strong suspension force in the magnetic suspension experiment and it also has characteristic peak in the XRD fig. In addition, we studied the factors which affect the properties of the sample during the sintering period, for example, the sintering temperature, the sintering time, et al.YBCO superconductor is not suitable to our desire because of its complex preparing technics and long preparing period. In order to find the suitable superconductor material which can be used in diphase doping, We prepared the BSCCO superconductor. BSCCO superconductor has many advantages, such as its simple preparing technics, low sintering temperature and strong ability to form superconducting phase. The Tc of the BSCCO superconductor prepared in this experiment is about 108K. It is a suitable superconducting material for ZnO diphase doping. The effects of Pb-doping and undoping on the BSCCO superconductor material are studied. From the experimental result, it clarified that Pb-doping is propitious to form Bi2223 superconducting phase.In low temperature, the high temperature superconductor has many interesting effects, for example, zero resistance, et al. As a semiconductor material, ZnO also hassome interesting phenomena, such as electroluminescence. We prepared the ZnO nano-particle by sol-gel method. In order to find the inherent relation between them and find the cooperating effect, We doped the ZnO nano-partical into the BSCCO material to form a diphase structure.From the experiment result of other peoples in our laboratory, the optimal melting temperature of ZnO is about 600°C.It is different from the sintering temperature of BSCCO superconductor. To resolve this problem, we improve the preparing technics of ZnO. The electroluminescence intensity of ZnO prepared by new technics is about 175. Different from traditional doping method, BSCCO powders are mixed with ZnO sol in this experiment. By this method, they can be mixed in nano-scale. In the end, the 1% ZnO doping and 3% ZnO doping samples are analyzed by XRD. From the result, it is easily to see that ZnO exist independly and have no effect to the forming of Bi2223 superconductor phase.