Effect of grain size on the dielectric properties of Lanthanumdoped PbTiO3 perovskite ceramics

Abstract

Lead lanthanum titanate, (PLT) ceramics were fabricated by conventional combustion technique and the influence of different sintering temperature (1170, 1200, 1230, 1260 and 1300 oC) at a fixed of sintering time for 2h on the microstructure and dielectric properties were investigated. The particle size of PLT ceramics which can be calculated by Scherer formula from XRD (x-ray diffraction) analysis is increased with increasing sintering temperature. The density of the samples also increases with increasing sintering temperature (Ts), which can be calculated from XRD pattern and can be observed from SEM (scanning electron microscope) technique. Dielectric properties of the samples were studied as a function of sintering temperature and frequency, where the maximum value of dielectric constant (εmax) increased with increasing Ts, but it decreased with increasing frequency, but the transition temperature independent on the applied frequency. The versus imaginary permittivity and dielectric loss with frequency at room temperature were investigated. The diffusion coefficient (γ) of PLT ceramics are decreased with increasing sintering temperature.