Effect of calcium stoichiometry on the dielectric response of CaCu3Ti4O12 Ceramics

TL;DR

This study investigates how varying calcium content in CaCu3Ti4O12 ceramics affects their structure and dielectric properties, revealing calcium deficiency reduces dielectric loss without compromising high dielectric constant.

Contribution

It provides new insights into the influence of calcium stoichiometry on dielectric response, using comprehensive characterization techniques on ceramics prepared via the oxalate precursor route.

Findings

Calcium deficiency reduces dielectric loss.

High dielectric constant is retained in calcium-deficient samples.

No oxygen vacancies detected in prepared ceramics.

Abstract

CaxCu3Ti4O12 polycrystalline powders with variation in calcium content were prepared via the oxalate precursor route. The structural, morphological and dielectric properties of the ceramics fabricated using these powders were studied using x ray diffraction, Scanning Electron Microscope along with Energy Dispersive X ray Analysis, Transmission Electron Microscopy, Electron Spin Resonance (ESR) spectroscopy and Impedance analyzer. The X ray diffraction patterns obtained for the x = 0.97, 1.0 and 1.1 powdered ceramics could be indexed to a body centered cubic perovskite related structure associated with the space group Im3. The ESR studies confirmed the absence of oxygen vacancies in the ceramics that were prepared using the oxalate precursor route. The dielectric properties of these suggest that the calcium deficient sample (x= 0.97) has a reduced dielectric loss while retaining the high dielectric constant which is of significant industrial relevance.