Numerical study on crystal growth process in YBCO film fabricated by TFA-MOD method

To fabricate high-J_c coated conductor of YBa₂Cu₃O_7-X (1 2 3) film, metal-organic deposition (MOD) process using precursor solution of trifluoroacetates (TFAs) is one of the most promising low cost non-vacuum methods. However, details of the growth process and the mechanism of 123-crystal growth are still unknown. To clarify the growth mechanism of 123-film, the growth processes of 123-crystals were studied by the experimental method and the numerical method. Microstructures of growing 123-crystals were revealed through transmission electron microscopy (TEM) observations of the specimens quenched during the growth of 123-crystals on LaAlO₃ (LAO) substrates. The growth process of faceted 123-crystals with various crystal orientations was simulated by the two-dimensional numerical method using c-axis and a-axis growth rate functions. The growth processes and the microstructures of 123-crystals were visualized by the simulation. The meandering of crystal boundaries, overgrowth of preferred oriented crystals, and the effects of initial distributions of nucleated crystals and particles were studied.