Preparation of epitaxial YbBa₂Cu₃O_7-δ on SrTiO₃ single crystal substrates using a solution process

We have prepared YbBa₂Cu₃O_7-δ (Yb-123) epitaxial films on SrTiO₃ (100) single crystal substrates by a metal organic decomposition (MOD) method. Precursor solution was prepared by dissolving ytterbium acetylacetonate, barium neodecanoate, and copper (II) 2-ethylhexanoate in a mixture of solvents containing toluene/pyridine/propionic acid. The precursor solutions were spin coated on the substrates and fired at 730-770 °C in 100-ppm oxygen atmospheres followed by 1 atm O₂ annealing. X-ray diffraction results from the theta-2theta, phi, and omega scans for the films revealed a (100) cubic texture. The full-width-at-half-maximum values for Yb-123 (103) and Yb-123 (005) were 1.5° (in-plane epitaxy, Δφ) and 0.73° (out-of-plane epitaxy, Δω), respectively. The highest T_c obtained for Yb-123 films was 87.2 K. The measured transport J_c was 6.4×10⁵ A/cm² at 77 K and self-field.