Dielectric and magnetic study of BaTi0.5Mn0.5O3 ceramics, synthesized by solid state sintering, mechanical alloying and chemical routes

A comparative study of the surface morphology, dielectric and magnetic properties of the BaTi0.5Mn0.5O3 (BTMO) ceramics has been carried out by synthesizing the samples in different routes. BTMO samples have shown single phased 12R type hexagonal structure with R3¯m space group. Interfacial effects on the dielectric properties of the samples have been understood by Cole–Cole plots in complex impedance and modulus formalism. It has been found that huge dielectric constant (103–106) at lower frequencies is largely contributed by the heterogeneous electronic microstructure at the interfaces of grains. Modulus formalism has identified the effects of both grain and grain boundary microstructure on the dielectric properties, particularly in chemical routed samples. The order of grain boundary resistivity suggests the semiconductor/insulator class of the material. The grain boundary resistivity of the mechanical alloyed samples is remarkably lower than the solid state and chemical routed samples. Some of the samples have exhibited signature of weak ferromagnetism at room temperature.