Epitaxial growth of superconducting GdBCO thin films prepared by fluorine-free MOD method

On account of the excellent characteristics of environmentally friendly and high growth rate, the growth of high-quality GdBCO superconducting films by fluorine-free metal-organic deposition method（FF-MOD） has attracted extensive attention. The nucleation and growth process of GdBCO superconducting film is explained by the nucleation and growth model on CeO₂ technical substrate. The process is mainly related to the transient liquid phase and the BaCeO₃ produced by the interface reaction. The transient liquid phase is beneficial to the nucleation and growth of the film, while the production of BaCeO₃ will inhibit the growth and reduce the quality of the film. By system optimization of sintering parameters such as oxygen partial pressure, sintering temperature, holding time, etc., affect the structure and superconducting properties of GdBCO films. Remarkably, a high critical current density（J_c） value of 2.8 MA/cm²（77 K, s.f.） was obtained in the GdBCO film grown on the metal substrate with CeO₂ cap layer under optimized deposition conditions. This work proves the feasibility of fabrication of high-performance GdBCO films on flexible metal substrates through FF-MOD and provides a guideline for improving the field performance of the films and prepare high-quality superconducting joints.