Optimization of processing parameters of YBCO films prepared by a dichloroacetic-metalorganic deposition method

The fluorine-free dichloroacetic-metalorganic deposition (DCA-MOD) method has been optimized and high-Jc YBa2Cu3Ox (YBCO) superconducting films over 1 MA cm−2 have been obtained. The effects of using a dilution solvent for the preparation of coating solutions were investigated for methanol and 2-methoxyethanol, respectively. The uniformity of the film thickness was improved by the use of 2-methoxyethanol. The two-step heat treatment for the preparation of the YBCO film led to a significant densification of the microstructure. Coated films were calcined at lower temperatures of up to 500 °C in a flowing oxygen atmosphere with a humidity of 7.2%. Conversion heat treatment was performed at various temperatures of 780–810 °C for 2 h in flowing Ar gas containing 1000 ppm oxygen with a humidity of 9.45%. SEM observations showed that the films have very dense microstructures with little pores. X-ray diffraction analysis showed that YBCO grains grew with a (00l) preferred orientation. A high critical current density (Jc) of 1.28 MA cm−2 (at 77 K and self-field) was obtained for the YBCO film prepared by the two-step heat treatment.