论文部分内容阅读
Six different compositions in Bi_2Sr_2Ca_2Cu_3O_y:Se_x. with x=0.0, 0.05, 0.1, 0.2, 0.3, 0.4 have been prepared by the solid state reaction method to explore doping of selenium in the system. Sintering at 847±4℃ and subsequent annealing at 827℃ has been carried out for different time periods. The samples have been characterized by X-ray powder diffraction (XRD). scanning electron microscopy (SEM), and measurement of resistance below room temperature has been carried out by four-probe method. Superconducting transition temperature (T_c) value shows dependence on Se concentration: the highest T_c(0)=94 K is observed for x=0.3. A detailed Auger electron spectroscopic (AES) analysis has been carried out to investigate the presence of Se in the grains of the superconductors. It has also been found that Se increases the T_c(0) value and promotes the formation of high temperature superconducting phase (2223). which coexists with low temperature phase (2212) in the sintered samples.
Six different compositions in Bi_2Sr_2Ca_2Cu_3O_y: Se_x. With x = 0.0, 0.05, 0.1, 0.2, 0.3, 0.4 have been prepared by the solid state reaction method to explore doping of selenium in the system. Sintering at 847 ± 4 ° C and subsequent annealing at The samples have been characterized by X-ray powder diffraction (XRD). Scanning electron microscopy (SEM), and measurement of resistance below room temperature has been carried out by four-probe method. Superconducting transition temperature (T_c) value shows dependence on Se concentration: the highest T_c (0) = 94 K is observed for x = 0.3. A detailed Auger electron spectroscopy (AES) analysis has been carried out to investigate the presence of Se in the The coexists with low temperature phase (2212) in the sintered samples.