Direct electrocaloric characterization of ceramic films

TL;DR

This paper introduces a new infrared imaging method using a polymer substrate to directly measure the electrocaloric effect in ceramic films, overcoming limitations of previous indirect methods and enabling better characterization for device integration.

Contribution

A novel direct measurement approach employing infrared imaging and a polymer substrate to accurately characterize electrocaloric effects in ceramic films.

Findings

Infrared imaging reduces measurement ratio to ~3.5.

Results validated with thermometric method.

Good agreement with indirect measurement approaches.

Abstract

Reliable and accurate characterization of the electrocaloric effect is necessary to understand the intrinsic properties of materials. To date, several methods have been developed to directly measure the electrocaloric effect. However, each of them has some limitations, making them less suitable for characterizing ceramic films, which rely almost exclusively on less accurate indirect methods. Here, a new approach is proposed to address the process of rapid heat dissipation in ceramic films and to detect the electrically induced temperature change before it thermally bonds with the surrounding elements. By using a polymer substrate that slows heat dissipation to the substrate and fast infrared imaging, a substantial part of the adiabatic electrocaloric effect in Pb(Mg1/3Nb2/3)O3-based ceramic films is captured. Infrared imaging provides a robust technique to reduce the ratio between the adiabatic and the measured electrocaloric temperature change in micrometer-sized ceramic films to a single-digit number, ~3.5. The obtained results are validated with another direct thermometric method and compared with the results obtained with an indirect approach. Despite different measurement principles, the results obtained with the two direct methods agree well. The proposed approach is timely and could open a door to verify the predicted giant electrocaloric effects in ceramic films, thus accelerating the process of their integration into functional devices.