Structure properties and relaxor characteristics of the phases transformation in BaTi0.5(Fe0.33Mo0.17)O3 perovskite ceramic

The effect of replacing titanium by iron and molybdenum in the B site on the structural and physical properties of BaTi0.5(Fe0.33Mo0.17)O3 polycrystalline sample was investigated by X-ray diffraction, scanning electron microscopy (SEM) as well as dielectric characterizations. Crystal phase, microstructure, and dielectric property of the ceramic were examined. A single hexagonal perovskite structure with space group P63/mmc was obtained at 1400 °C and stabilized at room temperature. The microstructural study of the sintered pellets revealed that the plate-like grains are the typical grain morphologies in this ceramic. The temperature dependence of the dielectric properties was investigated in the frequency range 1 kHz to 1 MHz. Three dielectric relaxations were observed in the present ceramic at the temperature ranges of 330-473 K, 473-550 K and 650-800 K with a maximum in the dielectric permittivity (ε'r ∼ 3518 at 443 K at 1 KHz, ε'r ∼4335 at 502 K at 1 KHz and ε'r ∼11,331 at 749 K at 1 KHz) that shifted to a higher temperature with increasing frequency. Temperature dependent variation of the dielectric constant showed a diffused phase transition which can be well described by fitting the modified Curie-Weiss relation, (1/ε'r-1/ε'r,max)=(T-Tm)γ/C.