Enhanced dielectric properties of doped barium titanate ceramics

Polycrystalline Ba1−xLax[Ti0.5(Fe0.5Nb0.5)0.5]1−x/4O3 [BT-LFN] ceramics with x=0, 0.02, 0.04 and 0.06 were prepared by the solid-state reaction method. The ceramics were subsequently examined at room temperature by X-ray diffraction to identify the phase. The structures of La doped samples were found to be mixed phases of tetragonal and rhombohedral structure. The variations of dielectric constant with temperature are very broad over a wide temperature range. We found the dielectric constant ∼3200 at room temperature and ∼10,000 at 350 °C for 6 mol% La-doped compositions at 1 kHz frequency. The hysteresis loop was observed having remnant polarization of 7.5 μC/cm2 at room temperature for 6 mol% La-doped sample. Complex impedance analysis was used to estimate its electrical conductivity as well as its corresponding activation energies.

► We have prepared the mixed phase BT-LFN ceramics for the first time.
► High dielectric constant has been found in 6 mol% La doped sample.
► Complex impedance analysis estimated its electrical conductivity.
► Hysteresis loop was observed with remnant polarization of ∼7.5 μC/cm2.