Direct visualization of antiferroelectric switching dynamics via electrocaloric imaging

TL;DR

This study uses infrared imaging to directly observe antiferroelectric switching in PbZrO3, revealing how device geometry and temperature gradients influence switching dynamics and electrocaloric effects.

Contribution

It introduces a high-speed electrocaloric imaging method to visualize and analyze antiferroelectric switching dynamics and effects in PbZrO3.

Findings

Switching is nucleation-limited and fast in homogeneous samples.

Gradient of thickness changes switching from nucleation-limited to propagation-limited.

Temperature differences induce simultaneous positive and negative electrocaloric effects.

Abstract

The large electrocaloric coupling in PbZrO3 allows using high-speed infrared imaging to visualize antiferroelectric switching dynamics via the associated temperature change. We find that in ceramic samples of homogeneous temperature and thickness, switching is nucleation-limited and fast, with devices responding in the milisecond range. By introducing gradients of thickness, however, it is possible to change the dynamics from nucleation-limited to propagation-limited, whereby a single phase boundary sweeps across the sample like a cold front, at a speed of c.a. 20 cm/s. Additionally, introducing thermostatic temperature differences between two sides of the sample enables the simultaneous generation of a negative electrocaloric effect on one side and a positive one on the other, yielding a Janus-like electrocaloric response.