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

Low-concentration $\text{YBa}_{2}\text{Cu}_{3}\text{O}_{7-x}$ (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 LaAlO3 (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/cm2 (at 77 K, 0 T) and a high pinning force of 7.2 GN/m3.