Impedance and modulus spectroscopy of Bi_0·5Na_0·5Nb_0·5Fe_0·5O₃ ceramic

Abstract The solid-state reaction method was used to prepare the lead-free Bi 0·5 Na 0·5 Nb 0·5 Fe 0·5 O 3 ceramic. The X-ray diffraction pattern of the prepared ceramic confirmed the formation of tetragonal crystal structure with P4mm space group. The field emission scanning electron microscopy analysis reveals densely packed grains of different shape and sizes. The average grain size was calculated to be 16.22 µm. Complex impedance spectroscopy was used to analyze the electrical response of the ceramic. The Nyquist plot shows the influence of both grain and grain boundary effects on the electrical properties of the material. The impedance analysis confirmed the non-Debye type of relaxation mechanism and negative temperature coefficient of resistance behaviour of the compound. The frequency dependent ac conductivity was found to obey Jonscher’s power law.