Effect of Ni doping on structural and dielectric properties of BaTiO 3

Abstract

Polycrystalline samples of Ba 1-xNi xTiO 3 (BNT), where x = 0, 0.03, 0.05, 0.07 and 0.10 have been synthesized by solid-state reaction technique. No phase change in the crystal structure has been observed with Ni doping in barium titanate up to x = 0.10, however a decrease in crystallite size, lattice strain, c/a ratio and grain size has been found with Ni doping. The different results presented may be related to, and are explained by, the grain size and its distribution in the ceramic bulk. Ni doping in BaTiO 3 exhibit many interesting features, such as shift in transition temperature, increasing diffuse phase transition and decreasing dielectric constant. The evolution from a normal ferroelectric phase transition to a diffuse phase transition has been observed with increasing Ni concentrations. The dielectric study of samples poled in magnetic field (data shown for BNT, x = 0.03 here) suggests that Tc and maximum dielectric constant increase with increasing magnetic poling strength along with decreasing nature of diffusivity thus showing multiferroic nature.