Abstract
The anisotropic microstrain and its relationship with the out-of-plane texture and superconducting properties of YBa2Cu3O7-δ (YBCO) films grown onto SrTiO3 (100) and LaAlO3 (100) single-crystal substrates by the chemical solution deposition sol-gel technique are considered. X-ray diffraction analysis present (00l) reflections from the YBCO phase in both films, with c-axis grain fraction values of 88% and 81% for the SrTiO3 and LaAlO3, respectively. The ω-scan measurements around the (005) reflection reveal a multi-layer structure for both films: three sub-layers with Δω = 0.35 °, 0.83 ° and 1.0 ° for YBCO/SrTiO3, and two sub-layers with Δω = 0.45° and 2.0° for YBCO/LaAlO3. Microstructural analysis using Debye-Scherrer and Williamson-Hall methods indicates that the YBCO films exhibit significant anisotropic microstrain, with the strain state being more homogeneous on LaAlO₃ than on SrTiO₃. The superconducting properties show a strong dependence on microstrain: The YBCO film on LaAlO₃ exhibit a higher onset critical temperature ( 92 K) compared to that grown onto SrTiO₃ ( 78 K), despite the latter having a higher degree of c-axis texture. This work demonstrates that anisotropic microstrain plays a dominant role in determining the superconducting properties of YBCO films grown by the chemical solution deposition technique, highlighting that structural texture alone is not the only factor governing superconducting performance.