Characterization of Ni-doped SrTiO3 ceramics using impedance spectroscopy

Abstract

The ceramic SrTiO3 (ST) with 0.2 atom % Ni doped was prepared by solid state reaction route. Average grain size of doped samples was measured and found to be 2.8 micron. The relative permittivity and dielectric loss of ST ceramics were found to increase with Ni-doping. The capacitance was measured at temperatures ranging from 4000 to 700 0C in the frequency range 10 Hz -13MHz. The grain and grain boundaries relaxation frequencies were shifted to higher frequency with temperature. The impedance measurements were conducted at 5000C to separate grain and grain boundary contributions. The bulk and grain boundary resistance was evaluated from impedance complex plain plot and equivalent Resistance- Capacitance (RC) circuit is proposed to model the experimental data.