Sol–gel chemistry of an aqueous precursor solution for YBCO thin films

A water based YBa₂Cu₃O_7−x (YBCO) precursor using a triethanolamine (TEA)/acetic acid complexing method to obtain YBCO thin films is described in detail. The influence of complexation behavior in the formation of transparent and homogenous sols and gels after the combination of Y, Ba and Cu—acetates, acetic acid and TEA has been studied by potentiometric titration and the results are compared with analytical simulations. The decomposition of the gel was studied by IR (infrared) and Thermal Gravimetric Analysis/Differential Thermal Analysis (TGA/DTA). The results in sol-gel chemistry can be used to decide on the necessities in the preparation of stable sol–gel precursors with a minimum amount of organic compounds. The sol–gel system was also used for the deposition of high textured superconducting thin films on STO substrates by dip coating. The synthesized YBCO showed a superconducting transition temperature of 90.95 K with narrow ΔT (2 K) for thin films. The results from X-ray diffraction show that the single phase YBCO was obtained. SEM pictures also indicate that the properties of the surface thin films are good.