Preparation of high purity phase (Bi, Pb)-2223 superconducting films by sol–gel method

Abstract

In this work, a (Bi, Pb)2Sr2Ca2Cu3O10+δ ((Bi, Pb)-2223) solution with good film-forming capability and chemical stability was synthesized through using metal acetates as raw materials, acrylic acid as an additive, and anhydrous methanol as a solvent to adjust the sol formula. Subsequently, (Bi, Pb)-2223 thin films were fabricated on LaAlO3 (LAO) single-crystal substrates via dip-coating technology at different heat treatment temperatures, and the structures and properties of (Bi, Pb)-2223 films were characterized. It was found that when the sol stoichiometric ratio of Bi : Pb : Sr : Ca : Cu was controlled at 1.9 : 0.35 : 2 : 2 : 3 and the gel film was heat-treated at 860℃ and dwelled for 120 minutes in an mixed atmosphere of N2 : O2 = 96 : 4, the prepared thin film with a pure (Bi, Pb)-2223 superconducting phase exhibited excellent biaxial texture, a dense surface structure, and had a Tc of 106 K and a ΔTc of 6 K. The microstructure analysis revealed a layered epitaxial growth of the film along the LAO substrate with a regular arrangement of atoms and a consistent interlayer spacing.