Characterization of epitaxial YBa2Cu3O7−δ films deposited by metal propionate precursor solution

Abstract

YBa2Cu3O7−δ(YBCO) filmswere deposited with a low-fluorine modified trifluoroacetate metalorganic deposition (TFA-MOD) methodon SrTiO3 single crystals and buffered Ni–W metallic tape with a thickness ranging from 450 to600 nm. The method consists in the substitution of yttrium and copper trifluoroacetateswith Cu and Y acetates dispersed in propionic acid. A reduced pyrolysis time with respectto the usual TFA method is obtained. Apart from CuO, no traces of second phasesare revealed by x-ray measurements. The films are compact without cracks, andexhibit a slight superficial porosity, but they still remain well connected, andtherefore the observed porosity does not affect either the critical current density orthe normal state resistivity values, which are indicative of high-quality YBCOfilms. Moreover, YBCO films were also obtained on Pd-buffered Ni–W, with aCeO2/YSZ/CeO2 buffer layer architecture. These films show good morphological, structural, and superconductiveproperties with high critical temperature (higher than 91 K) and critical current density higher than1 MA cm−2 at 77 K in self-field.