Enhanced Flux Pinning of YBCO Films by a Simple Self-Decoration Method

Low-concentration YBa
₂
Cu
₃
O
_7-x
(YBCO) precursor solutions (with metallic ion concentrations of 0.05-0.45 mol/L) were prepared. Deposition of the low-concentration precursor solutions led to the formation of YBCO nanodots on the LaAlO
₃
(LAO) substrates. After that, a high-concentration YBCO precursor solution (with a metallic ion concentration of 1.5 mol/L) was deposited on the nanodot-decorated LAO substrates to form continuous YBCO films. Results indicated that the morphology of the YBCO nanodot had a close relation to its solution concentration. In comparison with a pure YBCO film, the self-decorated YBCO films had a stronger flux-pinning force and a higher critical current density J
_c
under the magnetic field. Through optimization of the precursor solution concentration, a high-performance self-decorated YBCO film was obtained, with a J
_c
value of 7.1 MA/cm
²
(at 77 K, 0 T) and a high pinning force of 7.2 GN/m
³
.