Property Improvement of 600-nm-Thick YBCO Superconducting Films Fabricated Using a Pb-Modified MOD Method

In the fabrication of YBa
₂
Cu
₃
O
_7-δ
(YBCO) high-temperature superconducting films using a metal organic deposition (MOD) method, the formation of a/b-axis-orientated grains was a common detrimental factor. In this study, Pb addition was utilized to modify the MOD process, and significant improvements of YBCO film's properties were observed. Using the precursor solution prepared with or without lead acetate, YBCO films with the thickness of 600 nm were obtained for comparative study. It was found that the a/b-axis-orientated grains could be efficiently suppressed by Pb addition; thus, the critical current density was enhanced from 0.96 to 2.80 MA cm
^-2
(77 K, self-field) at the crystallization temperature of 780 °C. Pb was not detected in the final YBCO film. By analyzing the film samples quenched in the crystallization step of heat treatment, it was supposed that the Pb addition could help to optimize the nucleation of YBCO films and then evaporated because of its volatile behavior.