The effects of the firing temperature of YBCO coated conductors fabricated by TFA-MOD process

Abstract

We fabricated YBCO films on LAO substrates using the TFA-MOD method and evaluated the effects of the heat treatment temperature on the microstructure, degree of texture, and critical properties. The phase formation and microstructure were characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscopy (SEM) and the degree of texture was evaluated by pole-figure analysis.The firing was performed in the temperature range of 750–800°C and we found that the phase purity, grain size and orientation, degree of texture, and oxygen content varied with the firing temperature. The films fired at 775°C showed the highest critical temperature (TC-onset) of 89.5K and critical current (IC) of 40A/cm-width, which corresponds to a critical current density (JC) of 1.8MA/cm2. According to the results of the XRD, pole-figure, SEM and Raman analyses, these optimum critical properties can probably be attributed to the formation of a pure YBCO phase, stronger c-axis orientation and higher oxygen content.