Effect of precursor composition on Jc enhancement of YBCO film prepared by TFA-MOD method

Abstract Superconductive YBCO thin films have been prepared by trifluoroacetate (TFA) metalorganic deposition (MOD) method. Non-stoichiometric precursor solutions with cation ratios of Y:Ba:Cu = 1 +  x :2:3 ( x  = 0, 0.05, 0.1, 0.15 and 0.2) have been prepared by dissolving high purity Y 2 O 3 , BaCO 3 and CuO powders into trifluoroacetate. Coated film was calcined at lower temperature in a moisture-containing oxygen atmosphere. Superconducting YBCO films have been obtained by conducting a conversion heat treatment at higher temperature in a moisture-containing Ar (1000 ppm oxygen) atmosphere. Critical current density ( J c ) of YBCO film was increased with the amount of excess yttrium in YBCO film and revealed maximum J c for x  = 0.15 and decreased again for x  = 0.2. Four times higher J c was obtained for the film with x  = 0.15 compared to that of the film prepared from stoichiometric solution of Y:Ba:Cu = 1:2:3. It is considered that the densification of microstructure and absence of a -axis grains attributed to the enhancement of J c in the film made of non-stoichiometric solution.