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 flexo-electric 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 AT/AE can reach to 0.15 K center dot cm center dot 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.