Impedance spectroscopy and conduction mechanism of multiferroic (Bi0.6K0.4)(Fe0.6Nb0.4)O3

Polycrystalline (Bi0.6K0.4) (Fe0.6Nb0.4)O-3 material has been prepared using a mixed-oxide route at 950 degrees C. It was shown by XRD that at room temperature structure of the compound is of single-phase with hexagonal symmetry. Some electrical characteristics (impedance, modulus, conductivity etc.) were studied over a wide frequency (1 kHz-1 MHz) and temperature (25-500 degrees C) ranges. The Nyquist plot (i.e., imaginary vs real component of complex impedance) of the material exhibit the existence and magnitude of grain interior and grain boundary contributions in the complex electrical parameters of the material depending on frequency, input energy and temperature. The nature of frequency dependence of ac conductivity follows Joncher's power law, and dc conductivity follows the Arrhenius behavior. The appearance of P-E hysteresis loop confirms the ferroelectric properties of the material with remnant polarization (2P(r)) of 1.027 mu C/cm(2) and coercive field (2E(c)) of 16.633 kV/cm. The material shows very weak ferromagnetism at room temperature with remnant magnetization (2M(r)) of 0.035 emu/gm and coercive field (2H(c)) of 0.211 kOe. (C) 2014 Elsevier Ltd. All rights reserved.