Crystal growth of YBa/sub 2/Cu/sub 3/O/7-X/ thin films prepared by TFA-MOD method

Abstract

We have investigated an epitaxial growth of YBa/sub 2/Cu/sub 3/O/sub 7-X/ (YBCO) films on [001] SrTiO/sub 3/ substrates prepared by metal organic deposition (MOD) method using trifluoroacetate (TFA) solution. The YBCO films derived by this method have high J/sub C/ exceeding 5 MA/cm/sup 2/ at 77 K. We tried to clarify the growth mechanism of TFA-MOD YBCO films by X-ray diffraction, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) from viewpoint of both macro and micro scales. We prepared partially transformed films by quench during high temperature annealing under the conditions at 730, 740, 750 /spl deg/C, dew point = 20 /spl deg/C, P(O/sub 2/) = 130 ppm, and gas flow rate = 1000 cc/min. In the growth stage, the integrated intensities of /spl theta/-/sub /spl chi// scans for the films increased with annealing time, and after more annealing, the integrated intensities decreased. SEM and TEM images indicated an existing of the pores in the films. Avrami plot was performed on the growing YBCO films, and the Avrami exponents were 1 < n < 2.