A process for the preparation of high-quality and uniform large-scale Bi2212 superconducting films via the sol-gel method

Abstract

Bi2212 high-temperature superconducting films (HTSFs) have garnered significant interest as a potential material for the development of high-Tc microwave and terahertz (THz) devices due to their intrinsic Josephson effect. This work presents the utilization of the polyvinyl pyrrolidone (PVP) -assisted sol-gel dip coating (PSGDC) method for the large-scale production of Bi2212 HTSFs. Initially, Bi2212 HTSFs were prepared on a small-scale single crystal (001)-oriented SrTiO3 substrates, and comprehensive characterization of their phase purity, crystal structure, surface morphology, microstructure, stress state, and transport properties was conducted as a foundation for further analysis. By optimizing the crystallization conditions and PVP content, the Bi2212 HTSF achieved improved performance, including a higher onset superconducting transition temperature (Tc, onset) of 94 K, zero-resistance temperature (Tc, zero) of 86 K, and a critical current density (Jc) of 6.8 × 104 A/cm2 under a zero magnetic field at 2 K. Subsequently, the optimized process was applied to successfully prepare a large-scale Bi2212 HTSF with a diameter of 50 mm, exhibiting uniform phase composition, surface morphology, and superconducting properties, expanding the potential applications of Bi2212 HTSFs.

Keywords

• Sol-gel method
• Large-scale Bi2212 superconducting film
• PVP
• Superconducting performance