Phase field theoretical study of the electrocaloric effect in porous ferroelectric films

It has been experimentally observed that changes in the nanopore structure have a great impact on the ferroelectric domain structure, and then, the ferroelectric polarization value of the film can be controlled to increase the response of the electrocaloric effect. This phenomenon has great application prospects in refrigeration applications. In this study, the evolution process of the domain structure of porous ferroelectric films of Pb-0.7 Sr0.3TiO3 (PST) with different pore shapes was obtained through phase field simulation, and the influence of the pore shape on the performance of electrocaloric was predicted and analyzed. The results show that different shapes of pores can control the magnitude of the adiabatic temperature change. Among them, the anisometric ellipse shaped pore thin film can obtain a maximum adiabatic temperature change of 8 K, which is a significant improvement compared with traditional PST ceramics and PST non-porous films. This large adiabatic temperature change is due to the pore-induced domain switching. Therefore, controlling the pore shapes provides a new idea for optimizing the electrocaloric properties of porous ferroelectric thin films.