Structural and Impedance Characteristics of BiFeO3–BaTiO3 Multiferroics with Substitution of CeO2 for Relaxor Applications

Abstract Lead-free 0.7BiFeO3–0.3(BaTi1–xCexO3) ceramics with compositions of (x = 0, 0.01, 0.03, 0.05, and 0.07) were produced using a conventional solid-state reaction method. X-ray diffraction analysis was performed to examine the crystal structure and phases of the samples, verifying the rhombohedral perovskite structure of the compound. The lattice parameter and unit cell volume varied with the addition of Ce ions. Temperature and frequency variation impedance spectroscopic studies confirmed that the relaxation time and impedance real and imaginary parts decreased with increasing temperature, suggesting a normal conductive nature of the samples. The resistance values for both the grain and grain boundary followed a similar trend as the temperature varied. As the Ce doping level increased, the resistance within the grains surpassed that of the grain boundaries in all the samples. This is indicated by the reduction in the activation energy (Eτ) of the Ce-doped sample. The electric modulus and AC conductivity studies also followed a trend similar to that of the impedance studies. These studies confirm that the 0.7BiFeO3–0.3(BaTi1–xCexO3) sample is suitable for relaxor applications.