Two-dimensional X-ray diffraction characterization of growth mechanism of double perovskite-structured nanoparticles in thin films prepared via metal-organic decomposition

Doping of nanoparticles is one of the effective methods in order to obtain nanocomposite thin films with significantly improved performance. A complete understanding of nucleation and growth mechanism for nanosized doped particles and the orientation relationship between the particles and matrix material is essentially important for the enhanced functional properties of nanocomposite films. In this study, a two-dimensional X-ray diffraction (2D-XRD) technique was utilized to detect the orientation and phase evolution of Ba₂YNbO₆ (BYNO) doped particles within YBa₂Cu₃O_7−δ (YBCO). The textured and untextured information about the doped particles was extensively visualized via 2D-XRD spots and rings in comparison to 1D-XRD analysis. A systematic investigation of the nucleation and growth mechanism for the BYNO-doped YBCO nanocomposite film revealed the same orientation for BYNO particles near the LaAlO₃ (LAO) substrate, whereas the rest of the particles were detected with random orientation. The higher isotropic J_c with increased random orientation of the BYNO particles contributed significantly towards the improved superconducting properties of the thin films. Finally, a rich nucleation and growth model for the BYNO-doped YBCO nanocomposite film was established. This study aimed to analyze the orientation of the doped BYNO nanoparticles during the nucleation and growth of the YBCO film, with the main focus on demonstrating double perovskite-structured nanoparticles.