Crystalline characteristics and superconducting properties of Bi2212 thin films prepared by the Pechini sol-gel method: the effect of different substrates on the film growth

Bi2Sr2CaCu2O8+δ (Bi2212) superconducting thin films were prepared by the Pechini sol–gel method using nitrates as reactants. The precursor sol was deposited on LaAlO3(100) and MgO(100) single‐crystal substrates via the spin‐coating method. The results revealed that the phase formation temperature region of the pure Bi2212 phase and perfectly epitaxial Bi2212 films deposited on LaAlO3 substrates was significantly expanded to 8 K, indicating an improvement in crystallization of Bi2212 films. In addition, the phase formation temperature region of the pure phase and c‐axis‐grown Bi2212 films deposited on MgO substrates was reduced to 5 K because of the deterioration of epitaxy of Bi2212 films sintered at higher temperature. According to the investigation, the Tc,onset values of Bi2212 films grown on MgO substrates were about 92 K. Meanwhile, the optimal Tc,onset value of Bi2212 superconducting films grown on LaAlO3 substrates rose to 96 K.