Dielectric, AC-impedance, modulus studies on 0.5BaTiO3·0.5CaCu3Ti4O12 nano-composite ceramic synthesized by one-pot, glycine-assisted nitrate-gel route

Abstract A nano-composite electro-ceramic with the chemical formula 0.5BaTiO 3 ·0.5CaCu 3 Ti 4 O 12 (BTO–CCTO) has been synthesized by a glycine – assisted nitrate-gel route which is simpler and faster at relatively low temperature than the conventional solid-state synthesis method. X-ray diffraction (XRD) analysis showed the existence of BTO as a secondary phase alongside the major phase of CCTO. Transmission electron microscope (TEM) analysis of the composite shows that nano-particles (60±15 nm) were obtained. Further, scanning electron microscope (SEM) images show that the morphology consists of a few large grains of CCTO (~1–5 µm) embedded in small grains of BTO (~500 nm–1 µm) with a bimodal distribution. The impedance analysis shows two major contributions associated with the grains and the grain boundaries. Modulus analysis of this composite confirmed the presence of a Maxwell-Wagner type relaxation, which is temperature dependent. The activation energy value was found to be 0.80 eV, and this composite is electrically conductive due to the mobility of the ionized oxygen defects.