Role of Temperature and Duration of the Crystallization Anneal in the Texture Development of YBCO Prepared by TFA-MOD

The preparation of thin film Y₁Ba₂Cu₃O_7-x by metalorganic deposition using trifluoroacetic acid and metal acetates (TFA-MOD) has gained attention in recent years as a less expensive alternative to high vacuum synthesis. In this method, a sol-gel precursor containing the metal cations is converted to YBCO via a three-stage heat treatment consisting of calcining, firing, and oxygenation. The focus of this study was to optimize the process conditions during the firing heat treatment to obtain strongly textured, high-J_c YBCO. Samples were prepared by depositing the metalorganic precursor onto lang100rang SrTiO₃ substrates by dip coating. To ensure that film characteristics were attributable only to the crystallization anneal (i.e. firing), all other process steps were standardized based on earlier reports. The role of firing temperature was then investigated in the range of 700degC to 830degC with the duration held to four hours. After identifying the optimal processing temperature (in this case, 800degC) the duration was investigated in the range of one to six hours. A narrow processing window for obtaining a high degree of c-axis texturing was thereby identified and resulted in J_c values as high as 2.19 MA/cm² for the film fired for 4 hours at 800degC.