Polymorphs and dielectric properties of BaTi1−Ni O3

Abstract

Abstract We have studied the influences of the Ni doping on structural characterization and dielectric properties of BaTi1−xNixO3 (x = 0.0–0.1) prepared by conventional solid-state reaction. The composition is characterized by X-ray diffraction technique (XRD). Interestingly, there is the tetragonal-to hexagonal transformation in the crystal structure of BaTi1−xNixO3 at x = 0.06. Moreover, both hexagonal and tetragonal polymorphs coexist in the range 0.06 ⩽ x ⩽ 0.1. Complex dielectric constant (e), ac conductivity ( σ ac ′ ) , the normalized imaginary part of impedance Z ″ / Z max ″ and electric modulus M ″ / M max ″ have been studied as a function of frequency and composition at room temperature and in the frequency range up to 13 KHz. The real part (e′) of dielectric constant shows a step like relaxation behavior and has been explained qualitatively with the frame work of Kramers–Kronig transformation model. The universal dielectric response and the Jump relaxation model were considered and fitted for ac conductivity. The mismatch between the frequency dependence plots of Z ″ / Z max ″ and M ″ / M max ″ peaks is observed. The short range hopping model seems to be most appropriate model for the conduction mechanisms in BaTi1−xNixO3.