Structural, electrical, and multiferroic properties of Aurivillius (Bi7−xLax)Fe3Ti3O21 thin films

The effects of La3+- ion doping on the structural, electrical, and multiferroic properties of the six-layered Aurivillius-phase Bi7Fe3Ti3O21 thin film were investigated. A chemical solution deposition method was used to deposit the (Bi7−xLax)Fe3Ti3O21 (x = 0 and 0.6) thin films on Pt(111)/Ti/SiO2/Si(100) substrates. The formation of Aurivillius orthorhombic structures was confirmed by using X-ray diffraction and Raman spectroscopy studies. The (Bi6.4La0.6)Fe3Ti3O21 thin film exhibited a low leakage current density (1.84 × 10−6 A/cm2 at an applied electric field of 100 kV/cm) and a large remnant polarization (20.20 μC/cm2 at an applied electric field of 318 kV/cm) as compared to the Bi7Fe3Ti3O21 thin film. The enhanced electrical and multiferroic properties are ascribed to a reduced oxygen concentration and a structural distortion. Both thin films were weakly ferromagnetic at room temperature.