Structural characterization of multi-coated YBCO films processed by metal-organic deposition method

YBCO films were fabricated using the TFA-MOD process. The effects of film thickness on phase formation, degree of texture, microstructures, and critical properties were evaluated by X-ray diffraction. pole-figure, and transmission electron microscopy. The films were prepared with various thicknesses by producing multi-coated films by repeating the dip-coating and calcining processes. The microstructure and resultant critical current (I-c) and critical current density (J(c)) varied remarkably with film thickness: the Ic increased from 39 to 169 A/cm-width, while J(c) ranged from 0.85 to 0.92 MA/cm(2) with increasing number of coatings from one to three or four. Both values decreased when further coatings were applied as a result of microstructural degradation. It is believed that this decrease in 1, for the multi-coated film is partly due to the presence of a second phase, pores, and poor texture formability. The optimum thickness for maximizing both the I-c and J(c) values is believed to be in the range of 1.1-1.7 mu m. (C) 2008 Elsevier B.V. All rights reserved.