Origin of magnetic and dielectric response in single phase nano crystalline BiFeO3

Abstract

Stoichiometric and single phase synthesis of BiFeO3 is critical both in its particle industrial applications as well as in understanding the origin of its attractive dielectric and magnetic properties. In this study, BiFeO3 has been obtained at temperatures as low as 400 °C. Zero Fe+2/Fe+3 ratio, and absence of bismuth and oxygen non-stoichiometry have been probed by 57Fe Mössbauer spectroscopy. The appearance of different magnetic phases in 57Fe Mössbauer spectrum, MH hysteresis curve and exchange bias effect have been conferred on the basis of magneto-crystalline anisotropy and particle size distribution. Dependence of the dielectric response on the applied electric field reveals that the colossal dielectric response in BiFeO3 is dominated by extrinsic effects at grain-grain interface.