Investigations on Dielectric, Transport, and Ferroelectric Properties of Ca-Modified Bi0.80La0.20FeO3 Ceramic Synthesized by Solid State Reaction Route

Ca ion-modified Bi0.80-xCaxLa0.20FeO3 (BCLFO) polycrystalline samples (with x = 0.0, 0.03, 0.06, and 0.12), synthesized by solid-state reaction, and their structural, dielectric, transport, and ferroelectric properties are explored. Rietveld analysis of XRD data revealed that Ca ions provoke structural distortions followed by a phase transition for x = 0.12. The Williamson-Hall analysis revealed that Ca doping enhances the distortion in FeO6 octahedra, resulting in increases in strain and particle size. Scanning electron microscopy demonstrates a decrease in grain size with Ca doping. Room-temperature dielectric properties are remarkably enhanced with Ca incorporation when compared with those of undoped Bi0.80La0.20FeO3 (BLFO). Furthermore, the ac conductivity of these samples has been investigated from room temperature to 500 degrees C and different conduction mechanisms were found in different temperature regions. Ca incorporation prevents Bi evaporation and fluctuation of Fe oxidation states, which is reflected in better ferroelectric polarization versus electric field (P-E) loops than those of BLFO ceramics. However, this behavior reverses for x = 0.12 due to a structural rhombohedral to orthorhombic phase transition.