High-Performance $\hbox {GdBa}_{2}\hbox {Cu}_{3} \hbox {O}_{7 - {x}}$ Superconducting Film Prepared Using an Advanced Low-Fluorine Solution

An advanced low-fluorine GdBa₂Cu₃ O_7-x (GBCO) precursor solution was prepared using barium, gadolinium, and copper acetates as starting materials; lactic acid, methacrylic acid, and trifluoroacetic acid as additives; and methanol as a solvent. The gel-film cast from this solution consisted of Gd trifluoroacetate and fluorine-free Ba and Cu salts. The BaCO₃-free precursor was obtained through the pyrolysis of the gel film. After firing at 820 ^°C, the precursor was finally transformed to a phase-pure GBCO film. The critical current density (J_c) of the GBCO film was measured to reach 3.3 MA/cm² (at 77 K, 0 T), and its critical transition temperature (T_c) was 92.6 K. During the pyrolyzing of the film, the relatively small amount of released fluorinated gases resulted in the rapid fabrication of GBCO film.