Abstract

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.

摘要

随着小型化和高频化需求的增加，电子器件的制冷技术面临严峻挑战，而对铁电纳米材料电热效应（ECE）的研究使解决这些问题成为可能。由于铁电晶体表面的对称性破坏，表面的极化与晶体内部的极化不同，这会显着影响材料的电热性能。此外，考虑到自发极化和应力场之间的机电耦合，施加的应力对材料的 ECE 有很大的影响。在本文中，₃ (PTO) 纳米圆柱体。通过模拟获得了不同外推长度的应力-绝热温度变化（ATC）曲线，揭示了外推长度和应力对PTO纳米圆柱体的影响。本文研究结果可为下一代固态冷却装置的设计提供理论指导。