Influence of Lanthanum on the Microstructural and Dielectric Properties of Polycrystalline Ba(Ti_0.5Fe_0.5)O₃

Various polycrystalline Ba_1−xLa_x(Ti_0.5Fe_0.5)O₃ are prepared by using the standard solid state reaction technique. Pellet shaped samples prepared from each composition are sintered at 1200°C for 5 h. X-ray diffraction patterns of these compositions confirm the formation of a single phase perovskite structure. The lattice parameters are decreased but the average grain size increases with the increase of La content. The dielectric constant, dielectric loss and ac conductivity are studied as a function of frequency for various compositions, and their behaviors are explained on the basis of the Maxwell–Wagner model. A three-times enhancement of the dielectric constant is observed with the increase of La content.