Impedance spectroscopy study of LaMnO3 modified BaTiO3 ceramics

Ba0.97Ti0.97La0.02Mn0.04O3 nanocrystalline powder was prepared by chemical route with the help of soluble tartarate complex of Ti4+ ion. Preliminary X-ray diffraction analysis of crystal structure showed that a single-phase compound was formed exhibiting tetragonal system. Average crystallite size and particle size were observed to be between 27 and 33 nm, which were analyzed through XRD and transmission electron microscope respectively. Wide range impedance spectroscopy study from 200 to 600 °C showed the presence of both bulk and grain boundary effects up to 500 °C. The bulk conductivity indicated an Arrhenius-type thermally activated process and oxygen vacancies are the possible ionic charge carriers at higher temperatures. The variation of ac conductivity as a function of frequency indicated the possibility of hopping mechanism for electrical process in the system with a non-exponential type of conductivity relaxation.