Size-dependent phase transformation and its correlation with magnetic properties of multiferroic 0.8BiFeO3– 0.2CaTiO3 nanoparticles

Abstract Structural and magnetic properties of 0.8BiFeO3–0.2CaTiO3 (BF-20CT) nanoparticles were investigated systematically as a function of heat treatment at 500 °C, 650 °C, 800 °C and 950 °C of a sol-gel derived powder. The structural investigation by the Rietveld refinement revealed the phase transformation from monoclinic (Cc) to rhombohedral (R3c) structure. The lattice parameters, bond angles, bond distance, and unit cell volume significantly changed as temperature increases from 500 to 950 °C. TEM investigation has confirmed the size, morphology, and microstructure of the BF-20CT nanoparticles. Enhanced magnetization with the finite coercive field was observed as phase changed from monoclinic (Cc) to rhombohedral (R3c). The splitting in zero-field cooling (ZFC) and field cooling (FC) magnetization curves with a sharp peak in the ZFC curves revealing a spin-glass type behavior.