Thin films of BiFe_1-xAl_xO₃ (BFAlO, x = 0-0.03) were fabricated on ITO-coated glass substrates using the sol-gel technique. Comprehensive analyses conducted through X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy confirmed that all BFAlO thin film samples consist of both R3c and Pnma phases. The incorporation of Al was found to refine the grain size, markedly enhancing the density of the BFAlO thin film samples. X-ray photoelectron spectroscopy (XPS) analysis revealed that at an Al doping level of 0.02, there was a substantial reduction in the concentration of oxygen vacancies and Fe²⁺ ions within the films. These BFAlO thin film samples demonstrated a robust remnant polarization strength (2Pr = 132.94 μC/cm²) and a lower coercive field strength (2Ec = 690.52 kV/cm) when subjected to an applied electric field of 640 kV/cm. Additionally, after an aging period of 75 days, the samples showed commendable resistance to aging. The findings suggest that a moderate level of Al doping can significantly improve the ferroelectric stability of BFO films and bolster their resistance to the aging process.

Keywords: BiFeO₃, Al doping, Ferroelectric properties, Aging.