Dielectric anomalies in CaCu3Ti4O12 at high temperatures

Meini Zhang,Chunchang Wang,Guojing Wang,Kebiao Xu

doi:10.1007/s11434-012-5645-6

Abstract

We reported the dielectric properties of CaCu3Ti4O12 in the temperature range from room temperature to 800°C and the frequency range from 20 Hz to 10 MHz. Apart from the widely reported dielectric anomaly occurring around 200°C, three additional dielectric anomalies were found. The new anomalies are very sensitive to electrode sintering conditions and annealing atmospheres, indicating that they are dependent not only on the electrode-sample contact but also on oxygen vacancies.

Highlights

We reported the dielectric properties of CaCu3Ti4O12 in the temperature range from room temperature to 800°C and the frequency range from 20 Hz to 10 MHz
Since the perovskite-related CaCu3Ti4O12(CCTO) has been reported to have colossal and flat dielectric constants in the order of 103–105 in a wide temperature range around room temperature, which presents promising potential applications for kinds of devices, researchers have carried out a great deal of investigations on this material [1,2,3]
In addition to the stunning colossal dielectric behavior with its main features appearing in the temperature range below room temperature, a relaxor-like dielectric anomaly occurring in the temperature range from 400 to 600 K was considered as another surprising feature in CCTO [4,5,6]

Summary

Introduction

We reported the dielectric properties of CaCu3Ti4O12 in the temperature range from room temperature to 800°C and the frequency range from 20 Hz to 10 MHz. The new anomalies are very sensitive to electrode sintering conditions and annealing atmospheres, indicating that they are dependent on the electrode-sample contact and on oxygen vacancies. The results showed that apart from the above-mentioned dielectric anomaly, three additional anomalies related to oxygen vacancy and electrode-sample contact were found.

Results

Conclusion