Synchrotron 3D-RSM reveals the microstructure of superconducting YBa2Cu3O7−<i>x</i> films grown on various substrates

Abstract

Further unleashing the full potential of YBa2Cu3O7−x (YBCO), a premier high-temperature superconductor, for devices in advanced communication technologies hinges on the refinement of its fabrication process. In this work, a synchrotron three-dimension reciprocal space mapping (3D-RSM) technique, which offers a larger Q-space range and higher spatial resolution, was developed and used to analyze YBCO films grown on (001)-oriented LAO, STO, and MgO substrates. The 3D-RSM results reveal that epitaxial YBCO c domains dominate the films, with minor YBCO a domains in YBCO/LAO. The YBCO c domains present a consistent epitaxial relationship with the substrate STO and LAO, with the domain boundary parallel to the substrate [110] or [1¯10] axes. In contrast, YBCO/MgO films exhibit two distinct in-plane epitaxy orientations. Quantitatively measured lattice constants indicate the possible Tc-related oxygen vacancy condition therein. A 2-in. YBCO/MgO film, prepared by a homemade pulsed laser deposition system, verified the structural non-uniformity issues, suggesting room for further optimization. This study underscores the advantages of synchrotron-based 3D-RSM for microstructure analysis, which could support process improvement and performance optimization in high-frequency applications.