Colossal dielectric constants: A common phenomenon in CaCu3Ti4O12 related materials

TL;DR

This study reveals that a series of materials related to CaCu3Ti4O12 also exhibit colossal dielectric constants due to internal barrier polarization, expanding understanding of giant dielectric phenomena.

Contribution

It demonstrates that multiple Ln2/3Cu3Ti4O12 compounds show giant dielectric constants and provides detailed frequency-dependent analysis for Pr2/3Cu3Ti4O12.

Findings

Multiple compounds exhibit colossal dielectric constants.

Maxwell-Wagner relaxation process identified.

Internal barrier polarization likely causes high dielectric values.

Abstract

In the present work we demonstrate that in addition to the well-known colossal-dielectric-constant material CaCu3Ti4O12 also various members of the series Ln2/3Cu3Ti4O12 with Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Tm, exhibit giant values of the dielectric constant. Just as CaCu3Ti4O12, all these materials show a Maxwell-Wagner type relaxation process. For the best material, Pr2/3Cu3Ti4O12, we provide a detailed investigation of its dielectric properties in a broad frequency range up to 1 GHz. Polarization at internal barriers, most likely grain boundaries, seems to be the reason for the observed very high values of the dielectric constant. Taking into account the present results and those reported in literature