The preparation of c-axis epitaxial Bi-2212 films on STO(1 0 0) by sol–gel method

Bi2Sr2Ca1Cu2O8+δ (Bi-2212) films were grown on (1 0 0) oriented SrTiO3 (STO) substrate using sol–gel spin-coating method. The effects of heat treatment conditions and coating times on the phase formation and surface morphology were investigated using thermal analysis, optical microscope, X-ray diffraction, and scanning electronic microscopy. Mixed phases were formed from 820 to 840 °C, and Bi-2212 single phase was obtained at 830 °C for 3 h. c-axis epitaxial films with smooth surfaces were obtained by drying at 600 °C and coating for 5 times.