Microstructure and superconducting property of Bi2Sr2CaCu2O8 films quenched in different quenching methods

Abstract

The microstructure and superconducting property of Bi₂Sr₂CaCu₂O₈ (Bi-2212) films are compared after normalizing and quenching in cold bath. The suspension of 0.10 g finely ground Bi-2212 powder in 30 mL ethanol was prepared and used in the fabrication of films via electrophoretic deposition (EPD). The films were normalized and quenched in a cold bath post-partial melting at 970^oC, and annealed. It has been found that cold water quenching results in low c-axis oriented growth, weak intergrain connection, and low onset critical temperature (T_c-onset) and broad superconducting transition. The T_c-onset obtained is 77.45 K with a transition width (∆T) of 56.20 K. The results point to the existence of an optimal temperature difference in the partial melting phase.