Attractive electrocaloric and flexoelectric properties of Bi4Ti3O12 films

The electrocaloric (EC) effect is depended on the ferroelectric phase transition. To achieve a phase transition regulation near room temperature is still a challenging task. In this paper, the phase transitions and the flexoelectric effect of Bi4Ti3O12 have been investigated. The results indicate that the largest temperature change caused by phase transitions occurs at the Curie temperature, and the electrocaloric coefficient ΔT/ΔE can reach to 0.15 K·cm·kV−1. Under a pressure of 6.5 GPa, the Curie temperature can be regulated from 955 K down to 295 K. The controllable adjustment factor has reached an unprecedented value of 102 K/GPa. The predicted maximum flexoelectric coefficient of BIT is 56.6 nC/m. It indicates that BIT exhibits both excellent electrocaloric and flexoelectric properties. Our work provides a simple and effective approach towards the design of high performance EC materials near room temperature required for solid state refrigeration technology.