Stress effect on the electrocaloric properties of PbTiO3 nanocylinders with the consideration of surface polarization.

The refrigeration technology of electronic devices has faced severe challenges with the increasing demand for miniaturization and high frequency, and the research on the electrocaloric effect (ECE) of ferroelectric nanomaterials has made it possible to solve such problems. Due to the symmetry breaking on surfaces of a ferroelectric crystal, the polarizations on surfaces are different from those inside the crystal, which can significantly affect the electrocaloric properties of the materials. In addition, considering the electromechanical coupling between the spontaneous polarization and stress field, the applied stress has a drastic influence on the ECE of the material. In this paper, the extrapolation length is incorporated in the phase-field method based on the time-dependent Ginzburg–Landau equation to investigate the effects of different stress and surface polarization on the ECE of PbTiO3 (PTO) nanocylinders. The stress–adiabatic temperature change (ATC) curves with different extrapolation lengths are obtained through the simulations, which reveal the effect of extrapolation length and stress on the PTO nanocylinders. The results of this paper can provide theoretical guidance for the design of next-generation solid-state cooling devices. [ABSTRACT FROM AUTHOR]