Fabrication of high-jc YBCO films by the TFA-MOD Process using YBCO powder as precursor

YBCO thin films were prepared on LaAlO/sub 3/ (100) single-crystal substrates using the metal-organic deposition of trifluoroacetates (TFA-MOD). Unlike the normal TFA-MOD process, TFA-based solutions were prepared dissolving YBCO powder into the trifluoroacetic acid solvent. The solutions were coated on the substrates by spin coating, fired at the temperature up to 400/spl deg/C in 4.2% humid and oxygen atmosphere, fired again at the temperature region of 725-850/spl deg/C for 2 h in 4.2% humidity and 1000 ppm oxygen partial pressure, and finally oxygenated at 450/spl deg/C for 1 h. Similar to the normal TFA-MOD process, both microstructure and superconducting properties of YBCO films were highly sensitive to the firing temperature. Optimally processed YBCO films of /spl sim/250 nm thickness exhibited T/sub C,zero/ of 90 K and J/sub C/ of 2.9 MA/cm/sup 2/ at 77 K in a self-field. The present results clearly evidence that our cost-effective modified TFA-MOD process is applicable to the fabrication of YBCO coated conductors.