New MOD solution for the preparation of high J c REBCO superconducting films

High quality REBa2Cu3O x (RE = Y, Eu, Gd) films have been successfully fabricated by metalorganic deposition method using dichloroacetic acid. Metal acetates or oxide powders were dissolved in dichloroacetic acid and blue-colored get was obtained by drying. Coating solution was prepared by diluting blue gel in methanol. Coating solution was coated on single crystal (0 0 1) LaAlO3(LAO) by dip coating method. Processing parameters such as oxygen partial pressure, water vapor, ramping rate and pyrolysis temperature etc were controlled in order to obtain a good epitaxial film. 0.5 μm-thick film was obtained by single coating and with no crack after calcination heat treatment. Oxygen partial pressure was varied in the range of 100-1000 ppm and conversion heat treatment was carried out at the temperature range of 725-765 deg. C . A critical transition temperature (T c0) of 90 K and a critical transport current density (J c) of >0.5 MA/cm2 (77 K and self-field) were demonstrated for the GdBCO film grown on LAO single crystal substrate with a thickness of 0.5 μm. I c was determined by utilizing a transport measurement. SEM observations showed that the growth behavior of Y123 grains is different from that of TFA-MOD process