Fabrication of the YBCO films made by TFA-MOD using the 211-process

YBCO films were fabricated using TFA-MOD method with a precursor solution of Y₂Ba₁Cu₁O_x and Ba ₃Cu₅O₈ powders dissolved in trifluoroacetic acid (TFA) (the so called "211-film"). The effect of the calcining temperature on the phase formation, texture evolution, and thermal and critical properties were investigated. The microstructure and critical current density (J_c) of the 211-film varied significantly with the calcining temperature. The highest J_c of 1.9 MA/cm² (corresponding critical current is 39 A/cm-width) was obtained for the film calcined at 460°C, which is probably due to the enhanced degree of texture and increased film density and grain size. In addition, the microstructure and properties of the 211-films were compared with those of the film made using the conventional TFA-MOD method with the precursor of the acetates being dissolved In TFA. The J_c of the 211-film was higher than that produced by the conventional TFA-MOD method. TG, DTA, pole-figure, and SEM analyses indicated that the higher J_c was due to the improved microstructure resulting from the enhanced reaction kinetics in the 211-film.