Investigation of dielectric relaxation in BaTiO3 ceramics modified with BiYO3 by impedance spectroscopy

Abstract

The polycrystalline (1 − x)BaTiO3 − xBiYO3 ((1 − x)BT − xBY) (x = 0.2, 0.3) ceramics were prepared by a solid state reaction technique. X-ray diffraction (XRD) analysis shows the information of single phase compound with a perovskite structure. Well grain growth is found in SEM range. The dielectric studies shows that the diffusive factor (γ) is close to 1.8, which confirms that (1 − x)BT − xBY exhibits a diffuse phase transition. Moreover, impedance and electric modulus spectroscopy analysis in the frequency of (20 Hz–2 MHz) within temperature domain (250–400 °C) show that two relaxation processes are involved which are contributed to bulk and grain boundary effects. The plots of Z″ and M″ are dispersed with increase in frequency at different temperatures, which proves the dielectric relaxation. The plots of Z′ and the ac conductivity studies show the NTCR character of the compounds. The experimental value of conduction activation is 0.98 eV, which is near to the conduction activated energy of the electron from second ionization of oxygen vacancies.