The near room temperature electrocaloric cycling refrigeration in Bi5Ti3FeO15/BiFeO3 mesoscopic composites: Experiment and simulation

Abstract

Recently, the high efficient and environment–friendly electrocaloric cooling technology has become a hot topic. Unfortunately, the single process and extreme conditions have greatly limited its application. Due to the similar perovskite structure, Bi5Ti3FeO15 and BiFeO3 were selected to fabricate mesoscopic composites in this work to realize the double consecutive cooling effect. We propose that the non–collinear interfacial polarization is the origin of near room temperature electrocaloric cycling refrigeration. The electrons are trapped at the Bi5Ti3FeO15/BiFeO3 interfacial potential well, where the electrons possess discontinuous energy and jump by thermal activity. The structure, dielectric capacitance and ferroelectric polarization of the composite films were further analyzed. Finally, the performance of the mesoscale cooling device is simulated, which shows a promising avenue to high efficient double cycling refrigeration. More importantly, the results are helpful to understand the cycling principle of electrocaloric cooling.