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
$\hbox{GdBa}_{2}\hbox{Cu}_{3}\hbox{O}_{7 - {x}}$
(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
$\hbox{BaCO}_{3}$
-free precursor was obtained through the pyrolysis of the gel film. After firing at 820
$^{\circ}\hbox{C}$
, 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
$\hbox{MA/cm}^{2}$
(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.