Pyro-paraelectric and inverse pyroelectricity: Electrocaloric

Abstract

Pyro-paraelectricity is a phenomenon where materials consist of transient polarization in paraelectric phase/materials when exposed to temperature variations under stress/electric/strain gradients. This chapter examines its production processes, encompassing temperature-induced polarization, the flexoelectric effect, and polarization produced by external stimuli. A case study on the practical uses of pyro-paraelectricity in sensors and thermal energy harvesting emphasizes its potential to improve device functions. Additionally, the phenomenon of inverse pyroelectricity, referred to as the electrocaloric (EC) effect, is examined as a viable approach for cooling applications. EC cooling provides an eco-friendly substitute to conventional vapor compression cycle cooling, as it operates without a compressor, is scalable, and can attain superior efficiency. Investigations into active EC materials since the late 2000s have facilitated the creation of EC cooling devices capable of achieving temperature differentials higher than 8K. These improvements illustrate the capability of pyroelectric materials to produce substantial EC effects at low electric fields, resulting in high-performance EC cooling systems. This chapter also includes a case study analyzing the design of EC devices and associated factors, highlighting the potential of pyroelectric materials to transform cooling systems. © 2026 Elsevier Ltd. All rights reserved.