Enhanced ferroelectric properties of Ce-substituted BiFeO3 thin films on LaNiO3/Si substrates prepared by sol–gel process

The effects of Ce substitution on the structural and electrical properties of multiferroic BiFeO3 thin films grown on LaNiO3/Si(1 0 0) substrates by a sol–gel process have been reported. X-ray diffraction data confirmed the substitutions of Ce into the Bi site with the elimination of all secondary phases under a substitution ratio x = 15%. The dielectric constants of the films increased from 90 to ∼260 below 100 kHz with 5% molar Ce substitution and the films showed enhanced dielectric behavior. We observed a substantial increase in the remnant polarization (Pr) with Ce substitution and obtained a maximum value of ∼71 μC/cm2 by 5% molar Ce incorporation. The leakage current behavior at room temperature of the films was studied and it was found that the leakage current density decreased from 10−6 to 10−8 A/cm2 for 5% molar Ce-substituted films under a field 150 kV/cm. The reduction of dc leakage current of Ce-substituted films is explained on the basis of relative phase stability and improved microstructure of the material.