Influence of starting solution composition on superconducting properties of YBCO coated conductors by advanced TFA-MOD process

Abstract

We have investigated the influence of the starting solution composition on both the microstructure and superconducting properties of YBa2Cu3O7−x (YBCO) films deposited on CeO2 buffered IBAD-Gd2Zr2O7/Hastelloy substrates and (100)-oriented LaAlO3 single crystals by the advanced TFA-MOD process. The starting solutions with different compositions of molar ratios of Y:Ba:Cu=1.0:1.0–3.0:3.0 were studied. The critical current density (Jc) values of the YBCO films fabricated from Ba-rich (molar ratio of Ba/Y>2) starting solutions were low. On the other hand, high Jc values were recognized, when the YBCO films were prepared from the Ba-poor (molar ratio of Ba/Y<2) starting solutions. The highest Jc value of 3.5MA/cm2 (77K, self-field) was obtained at a Ba/Y molar ratio of 1.4–1.6. Finally, the extremely high critical current (Ic) value of 735A/cm-width (77K, self-field) was obtained, when the YBCO film was fabricated on CeO2 buffered IBAD-Gd2Zr2O7/Hastelloy substrates by using the Ba-poor (Ba/Y=1.5) starting solution.