Effect of substrate orientation on the structures and properties of BiFe_0.91Zr_0.09O₃ thin films

Utilizing MgO single crystal substrates with varied orientations (〈100〉, 〈110〉 and 〈111〉), BiFe_0.91Zr_0.09O₃·(BFZO) films with diverse orientations were synthesized on LaNiO₃·(LNO) underlying electrodes employing the sol–gel technique, thereby establishing BFZO/LNO/MgO multilayer film configurations. This research comprehensively examines the impact of orientation on the crystal lattice, microstructure, defect density, and electrical characteristics of BFZO films. The outcomes reveal that the fabricated films demonstrate favorable epitaxial growth relationships and compact surface morphologies. X-ray photoelectron spectroscopy (XPS) analysis demonstrates that the films oriented along the  〈111〉 direction exhibit the least amount of Fe²⁺ and oxygen vacancy defects. Moreover, these films show the highest remanent polarization (2P_r = 85.31 μC/cm²), the lowest leakage current density, and exceptional resistance to aging. These findings suggest that the orientation of the films plays a crucial role in influencing their structural and electrical characteristics, thereby holding significant implications for enhancing the fabrication of functional films.