Studies of structural, impedance and magnetic properties of (BiNa)1/2(Fe2/3Mo1/3)O3 nanoceramics

Abstract

Very low magnetic moment and high leakage current are the two major disadvantages which restrict the application of BiFeO3 (BFO). We have doped Na+ and Mo6+ in Bi3+ and Fe3+ site respectively to make BiFeO3 more users friendly. Polycrystalline samples of pure BiFeO3 (BFO) and (BiNa)1/2(Fe2/3Mo1/3)O3 (BNFMO) are synthesized by solid-state reaction technique. Phase formation and crystal structure of the samples are analyzed by X-ray diffraction (XRD). The crystallite size obtains from XRD data shows the formation of BNFMO nanoceramics. Average grain size of the sintered BNFMO pellet is found to be 0.32 μm with scanning electron microscopy (SEM). Elemental compositions of BNFMO are checked with energy dispersive X-ray spectroscopy (EDX). Dielectric and impedance studies of the material are done in a wide temperature range (30–475 °C) at different frequency (100 Hz – 1 MHz). Arrhenius relation is used to explain the dc conductivity and the value of activation energy is 0.80 eV for grain (200–400 °C) and 0.95 eV for grain boundary (225–400 °C). The value of activation energy predicts that the second ionization of oxygen vacancies is responsible for conduction mechanism in BNFMO. Ac conductivity follows Jonscher's universal power law. P–E loop with large remnant polarization (Pr) proves that leakage current is reduced due to Na and Mo co-doping. The low value of the leakage current will make BiFeO3 more users friendly. Nonlinear M–H curve with enhance magnetic moment compare to parent BiFeO3 will also increase the industrial application of BiFeO3.