Dielectric relaxation and conductivity studies of (K0.5Bi0.5)(Fe0.5Nb0.5)O3 ceramics

Abstract

The polycrystalline sample of (K0.5Bi0.5)(Fe0.5Nb0.5)O3 was synthesized by a high-temperature solid-state reaction technique. The material crystallizes in cubic structure at room temperature. The dielectric properties of the material were investigated in a temperature range from 30-200 °C in the frequency range (102-107 Hz). Impedance data is well fitted using proper equivalent circuit composed of a parallel resistance and capacitance in series with a parallel resistance, constant phase element and a capacitance. The compound shows a typical negative temperature coefficient of resistance type (NTCR) behavior like that of semiconductors. Modulus spectroscopy and dielectric conductivity formalism were employed to study dielectric relaxation phenomena in the material. The frequency dependence of conductivity is well fitted to Jonscher's single power law. © 2012 VBRI Press.