Effect of Er/Y addition on the growth and superconductivity of Bi2212 films.

In order to increase the critical current density of Bi2212 superconducting films to broaden their application areas. A series of Bi 2 Sr 2 CaCu 2 O 8+ δ - x RE 2 O 3 (RE = Er/Y) ( x = 0, 0.04, 0.08, 0.12, 0.16, 0.20) thin films were prepared by the sol-gel method. The structure, morphology and superconductivity of the RE 2 O 3 doping films were characterized in detail. The effect of RE 2 O 3 on the superconductivity of Bi2212 superconducting films was investigated. It was shown that the Bi2212 films were (00 l ) epitaxially grown. The in-plane orientation relationship between the Bi2212- x RE 2 O 3 and the SrTiO 3 was Bi2212[100](001)//SrTiO 3 [011](100). The grain size in the out-of-plane direction of Bi2212 tends to increase with the amount of RE 2 O 3 doping. Doping with RE 2 O 3 had no significant effect on the anisotropy of Bi2212 crystal growth, but inhibited the agglomerative growth of the precipitated phase on the surface to a certain extent. Furthermore, the conclusion was that the superconducting transition temperature ( T c,onset ) was almost unaffected, while the zero resistance transition temperature ( T c,zero ) continued to decrease with increasing doping level. The thin film samples Er2 ( x = 0.04) and Y3 ( x = 0.08) exhibited the best current-carrying capacity in magnetic fields.