Structure and electrical properties of Ba(In0.5Nb0.5)1-xTixO3 ceramics

Abstract

Lead-free Ba(In 0.5 Nb 0.5) 1-x Ti x O 3 (0 ≤ x ≤ 1) ceramics was synthesized using a standard high temperature solidstate reaction method and sintered at 1400°C/4 h (except the pure BaTiO 3 which was sintered at 1300°C/4 h). The ceramics was characterized by X-ray diffraction, scanning electron microscopy, dielectric, impedance and AC conductivity studies. The crystal structure of the compounds was found to be cubic (with the space group Pm3m) for x = 0, 0.25 and 0.50 and tetragonal (P4/mmm) for x = 0.75 and 1.0. Increase in Ti-content in the ceramic samples leads to the decrease in unit cell volume while the values of real as well as imaginary parts of dielectric constant and AC conductivity increase. Complex impedance spectroscopy analysis indicated the negative temperature coefficient of resistance. AC conductivity data supported the hopping type of conduction in the system and obeyed Jonscher's power law. The real and imaginary parts of dielectric constant and AC conductivity data fit excellently well with an exponential function.