Effect of nickel and lithium co-substituted barium titanate ceramics on structural and dielectric properties

The effect of Ni and Li co-substitution on the structural and dielectric properties of barium titanate (BaTiO₃) ceramics has been investigated. Ni and Li co-substituted barium titanate (BT) with general formula Ba_(1−x)Li_xNi_x/2TiO₃ where x = 0, 0.02, 0.04, and 0.08 is synthesized using microwave-assisted heating. This synthesis process extraordinarily reduced the processing time to 1 h, which includes heating and the dwell durations. The XRD investigation confirmed the formation of a single phase tetragonal structure with a space group of P4mm. The surface morphology of the sintered samples exhibits a high density and a homogeneous distribution of the grains. Impedance analyzer was used to measure the dielectric constant and loss tangent values at different frequencies as well as at various temperatures range. Ni and Li co-substituted BaTiO₃ shows many interesting features, such as shifting of phase transition towards higher temperature, increasing in dielectric constant, decreasing in dielectric loss and increasing in diffuse phase transition with increased frequency. The activation energy of all samples was investigated using Arrhenius plots.