Development of Fluorine-free MOD Precursor Solution for fabricating REBCO Superconducting Films

New precursor solution with dichloroacetic acid (DCA) was developed for fabricating high Jc REBCO film. DCA based-precursor solution was coated on LaAlO3 (001) substrate by dip coating method. Processing parameters such as oxygen partial pressure, water vapor, ramping rate and pyrolysis temperature were controlled in order to obtain a good epitaxial film. The film with thickness of 0.5 micrometer was obtained by single coating and no crack was observed at calcined films. Oxygen partial pressure was controlled in the range of 100 - 1,000 ppm and conversion heat treatment was carried out at the temperature range of 705-765 degrees C. A critical transition temperature (Tc) of 90 K and a critical transport current density (Jc) of >0.5 MA/cm2 (77 K and self-field) were obtained for the GdBCO film. It is thought that fluorine-free MOD solution using DCA is promising precursor solution for fabricating high quality REBCO films.