Structural, optical and conductivity properties of BaTi1−xNixO3

Abstract

In this work, we studied the effects of Ni doping on the structural, optical, ac conductivity and dielectric loss properties of BaTi1−xNixO3 (0≤x≤0.1, in a step of 0.02) prepared through conventional solid-state reaction. Detailed analyses of XRD patterns and Raman spectra indicate that Ni dopants incorporate into the Ti sites of BaTiO3 host lattices, and the tetragonal-to-hexagonal transformation takes place at a threshold concentration of xc=0.06. Optical band gap value deduced from UV–Vis spectra decreases with the increase in Ni concentration, which confirms that Ni-doping into BaTiO3 causes the change in their electronic levels associated with lattice defects, creates new energy level to the forbidden gap, and, therefore, results in the reduction in the band gap. Study of ac conductivity indicates that conduction mechanism can be explained by the correlated barrier hopping (CBH) model.