Structural properties of ferroelectric characteristics of mixed NiTiO₃-BiFeO₃ thin film by the sol-gel method

In this study, we studied the structural properties and ferroelectric characteristics of the pure BeFiO₃ (BFO) and mixed NiTiO₃-BiFeO₃ (NTO-BFO) thin films by the sol-gel method and spin-coating process. We employed atomic force microscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, X-ray diffraction, and transmission electron microscopy to analyze the surface roughness, chemical bonding, surface morphology, crystal structure, and film microstructure of both thin films. The mixed NTO-BFO film showed better electrical characteristics, such as a smaller leakage current density (9.66 × 10⁻⁵ A/cm²) and a higher remanent polarization (59.02 μC/cm²), than the pure BFO one. Moreover, the mixed film demonstrated diamagnetism behavior in the magnetic-hysteresis loop. This finding may be attributable to the NTO film deposited on the BFO film avoiding the volatilization of Bi ions and increasing the domain walls, hence giving rise to a decreased leakage current and an increased ferroelectric characteristic.