Dispersion studies of La substitution on dielectric and ferroelectric properties of multiferroic BiFeO3 ceramic

Abstract Lanthanum La-substituted multiferroic Bi 1− x La x FeO 3 ceramics with x = 0.0, 0.05, 0.10, 0.15, 0.20 and 0.25 have been prepared by solution combustion method. The effect of La substitution for the dispersion studies on dielectric and ferroelectric properties of Bi 1− x La x FeO 3 samples have been studied by performing x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), density, dc resistivity and dielectric measurements as well as characterizing the polarization-field hysteresis loop. The results of prepared samples are compared with those of bismuth ferrite (BiFeO 3 ). In the measuring frequency of 10 KHz to 1 MHz, the dielectric constants and dielectric losses for samples x = 0.20, 0.25 are almost stable and exhibited lowest dielectric loss close to 0.1. The resistivity of Bi 1− x La x FeO 3 samples reaches a maximum value of 10 9 ohm-cm, which is about three times higher than that for pure BiFeO 3 . The results also show that stabilization of crystal structure and nonuniformity in spin cycloid structure by La substitution enhances the resistivity, dielectric and ferroelectric properties. Furthermore, the substitution of rare earth La for Bi helps to eliminate the impurity phase in BiFeO 3 ceramic.