Size dependent structural, vibrational and magnetic properties of BiFeO3 and core-shell structured BiFeO3@SiO2 nanoparticles

Abstract

Bulk BiFeO3, BiFeO3 nanoparticles and core-shell structured BiFeO3@SiO2 nanoparticles were synthesized by solid state reaction method, sol-gel and Stöber process (SiO2 shell) respectively. Transmission electron microscopy image confirmed the core-shell structure of BiFeO3@SiO2 nanoparticles with BiFeO3 core ∼50-90 nm and SiO2 shell ∼16 nm. X-ray diffraction and FTIR spectroscopy results showed the presence of distorted rhombohedral structure with R3c space group in all three samples. The magnetic measurement indicated the existence of room-temperature weak ferromagnetism in core-shell BiFeO3@SiO2 nanoparticles and BiFeO3 nanoparticles, whereas bulk BiFeO3 showed antiferromagnteic nature. Electron Spin Resonance results confirmed the enhancement in magnetic properties of coreshell structured BiFeO3@SiO2 nanoparticles in comparison with BiFeO3 nanoparticles and bulk BiFeO3. © 2014 AIP Publishing LLC.