Enhanced Flux Pinning and Critical Current Density of $ \hbox{BaZrO}_{3}$-Doped $\hbox{Y}_{0.75} \hbox{Gd}_{0.25} \hbox{Ba}_{2} \hbox{Cu}_{3} \hbox{O}_{7-{\rm x}}$ Superconducting Films Prepared Using Advanced Low-Fluorine Solution

Y
_0.75
Gd
_0.25
Ba
₂
Cu
₃
O
_{7- x}
(YGBCO) films with BaZrO
₃
(BZO) inclusions as pinning centers were prepared on LaAlO
₃
(00 l) substrates by metal-organic deposition via introducing zirconium (IV) acetylacetonate into the advanced low-fluorine YGBCO precursor solution. The BZO defects in the YGBCO film were found to induce the formation of a-oriented YGBCO grains on the film surface. An annealing process at a high temperature of 805 °C can completely eliminate the a-axis grains. The introduction of BZO defects in c-oriented YGBCO film can improve the film critical current density (J
_c
) and flux pinning of the films. Through the introduction of BZO nanostructure, the J
_c
of the YGBCO film processed at 805 °C was improved from 3 to 9 MA/cm
²
at 77 K and 0 T. The flux pinning force density Fp also reached a high value of 38 GN/m
³
at 65 K and 0.5-1 T.