Electrocaloric properties and critical behavior of a ferroelectric thin film

In this manuscript, the effective field theory (EFT) is used to investigate ferroelectric, thermal, and electrocaloric properties of a ferroelectric thin film. In this regard, the influence of the electric and transverse fields on the aforementioned properties are systematically investigated. Through a detailed analysis, investigations of electrocaloric performance with particular focus on the applied electric field and transverse field are elucidated. As expected, a high electrocaloric effect (ECE) is obtained, however the magnitude corresponding to this effect is enlarged and caused a dielectric breakdown due to the contribution of the transverse field Ω. The peaks corresponding to ECE increase and shift towards higher temperatures after an appropriate increase of the applied electric field. Furthermore, the critical temperature can shift to either lower and higher temperatures compared with the corresponding underlying parameters. On the contrary, the transverse field reduces the peak’s maxima, and therefore the ECE becomes weaker. The influence of the surface exchange interaction and thickness of the film on the entropy change (ΔS/J) and adiabatic temperature change (ΔT/J) were also investigated. This work reveals a large contribution of the applied electric field, surface coupling, and transverse field on the phase transitions. Consequently, the magnitude and ΔT/J can be controlled by appropriately choosing the system’s parameters.