▎ 摘　　要

Bi1.6Pb0.4Sr2Ca2Cu3Oy superconductor samples doped with graphene oxide (GO) in different weight percentages (0 wt.%, 0.002 wt.%, 0.004 wt.%, and 0.010 wt.%) were synthesized by a solid-state reaction method and then characterized. The structure and morphology of the samples were characterized by x-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). XRD analysis revealed that all the samples contained Bi-2223 and Bi-2212 phases with a small amount of impurity phase. The results showed that GO doping did not change the lattice parameters or structure of the samples dramatically, indicating that GO remains between the grains, playing a role of weak links. SEM revealed that all the samples had randomly distributed grains with plate-like shape. A decrease of the pore size, and hence enhanced densification and better connections between the grains, was observed for the 0.010 wt.% GO-doped sample when compared with the other samples. Magnetization measurements (M-T) were used to determine the onset critical temperature (T-c) of each sample, revealing that T-c decreased with increasing GO content up to x = 0.004 but increased slightly for the GO content x = 0.010. The results also showed that the highest onset critical temperature, T-c (75 K) and Josephson current, I-0 (5.89 mu A) values were obtained for the 0.010 wt.% GO-doped sample, which thus represents the optimum doping amount to improve the magnetic and structural properties.