Insights on the role of defects on the magnetic and magneto electric coupling effects in nano BiFeO3

Abstract

BiFeO3 nanoparticles prepared through sol-gel route using citric acid are studied for their structural, magnetic and magneto-electric coupling effects and are compared with that of calcined BiFeO3 particles prepared with tartaric acid as the fuel. Nanoparticles of BiFeO3 prepared with the use of citric acid were observed to be more strongly ferromagnetic and weakly ferroelectric, as compared to that of the bismuth ferrite nanoparticles prepared using tartaric acid as the fuel.Magneto-electric coupling effects were studied in BiFeO3 prepared by these methods using Raman spectroscopy. These results were further confirmed based on the direct experimental evidence in terms of the variation of polarization with respect to electric field (P-E loop) studies carried out in the nanoparticles of BiFeO3 under the application of magnetic field.This study brought out new insights on the important role of defects for the observed variations in magnetic and hence magneto-electric coupling effects in BiFeO3 nano particles prepared using different fuels, as elucidated based on the Mössbauer studies.