Effects of (Gd,Mn)-doping on ferroelectric properties of BiFeO3 thin films prepared using chemical solution deposition

Polycrystalline BiFeO₃ (BFO) and (Gd, Mn) co-doped BiFeO₃ (BGFMO) thin films were prepared on Pt(111)/Ti/SiO₂/Si(100) substrates by a chemical solution deposition method. Formation of rhombohedrally distorted perovskite crystal structure for the BFO and the BGFMO thin films was confirmed by an x-ray diffraction and a Raman analysis. Improved ferroelectric properties were observed from the BGFMO compared to BFO thin film. The remnant polarization (2P_r) 105 μC/cm² and the coercive field (2E_c) 959 kV/cm were observed from the BGFMO thin film at a maximum applied field of 1464 kV/cm. The leakage current density of the BGFMO thin film (3.9×10^-6 A/cm² at 100 kV/cm) was three orders of magnitude lower than that of the BFO thin film. In the BGFMO thin film, no polarization fatigue was observed up to 4.44×10⁸ switching cycles. The controlled leakage current and improved ferroelectric properties for the co-doped thin film were well correlated with the change in microstructure and the compensation of oxygen vacancies.