Investigation on Structural Modification of CaCu3Ti4O12 by Eu3+ Doping and Its Correlation with Dielectric and Impedance Spectroscopy

Abstract

Eu-doped Calcium Copper Titanate (CCTO) ceramics were synthesized via the solid-state reaction technique and systematically characterized for their structural and dielectric properties. X-ray diffraction (XRD) and Rietveld refinement analyses confirmed that doping of Eu³⁺ ion significantly affects the structure of the Ti–O₆ polyhedra, which in turn influenced their dielectric properties. Impedance spectroscopy revealed that both grain and grain boundary contributions significantly impact the overall conductivity of the Eu-doped CCTO, with the grain boundary resistance dominating at lower temperatures. The high activation energies associated with grain boundaries suggest the presence of a Schottky barrier potential, which likely contributes to reducing the dielectric loss in the material. Scaling analysis provided insights into the relaxation mechanisms associated with grains and grain boundaries, revealing distinct relaxation zones and highlighting the anisotropic nature of charge distribution at grain boundaries. Overall, the study confirms that Eu doping in CCTO ceramics enhances their dielectric properties by influencing structure of the host matrix as well as grain interior and grain boundary characteristics. These findings offer critical insights into the material’s behavior and present opportunities for optimizing CCTO-based ceramics for advanced high-performance electronic applications.