Lum C Y, Lim K-G, Chew K-H
Center for Theoretical and Computational Physics, Department of Physics, University of Malaya, 50603 Kuala Lumpur, Malaysia.
Department of Foundation Studies, RCSI UCD Malaysia Campus, 10450 Penang, Malaysia.
J Phys Condens Matter. 2022 Aug 12;34(41). doi: 10.1088/1361-648X/ac7e99.
We revisit the Kittel's model of antiferroelectricity by extending the model to study the phase transitions, hysteresis loop behaviors and electrocaloric effect (ECE) of antiferroelectrics (AFEs). By considering both the first- and second-order AFEs, explicit expressions for the physical and staggered polarizations of AFEs in the stable states are derived. We also obtain the analytical solutions for describing the dielectric susceptibilities of AFEs in the AFE and paraelectric (PE) phases. Coercive fields in AFE are also derived and studied. To verify the usefulness of the Kittel's model of antiferroelectricity, we apply the model to systematically investigate the phase transitions, hysteresis loops and ECEs of PbZrO(PZO). By adopting appropriate values of the Kittel's parameters for first-order transition, analytical and numerical results are obtained and discussed. Our results show that PZO exhibits a complex temperature ()-electric field () phase diagram, consisting of the AFE, ferroelectrics, ferrielectric, PE and mixed phases. Thephase diagram is qualitatively agreed with the new AFE model that was derived based on symmetry by Tolédano and Khalyavin (2019B024105). We found that the calculated zero-field dielectric susceptibility is qualitatively and quantitatively agreed with experimental results. We show that the polarizations and dielectric susceptibilities of PZO in heating and cooling deviate from each other, as expected for the first-order materials. Our calculated results also reveal that the ECE in PZO has an electro-heating of Δ≈ +6.5 °C and an electro-cooling of Δ≈ -4.0 °C, respectively, which are comparable to the experimental results.
我们通过扩展基特尔反铁电模型来重新审视该模型，以研究反铁电体（AFE）的相变、磁滞回线行为和电卡效应（ECE）。通过考虑一阶和二阶反铁电体，推导了反铁电体在稳定状态下物理极化和交错极化的显式表达式。我们还获得了描述反铁电体在反铁电相和顺电相（PE）中介电常数的解析解。还推导并研究了反铁电体中的矫顽场。为了验证基特尔反铁电模型的实用性，我们应用该模型系统地研究了PbZrO（PZO）的相变、磁滞回线和电卡效应。通过采用一阶转变的基特尔参数的适当值，获得并讨论了分析和数值结果。我们的结果表明，PZO呈现出复杂的温度（）-电场（）相图，由反铁电相、铁电相、铁电介质相、顺电相和混合相组成。该相图与托莱达诺和哈利亚文（2019B024105）基于对称性推导的新反铁电模型在定性上一致。我们发现计算得到的零场介电常数在定性和定量上与实验结果一致。我们表明，PZO在加热和冷却时的极化和介电常数相互偏离，这是一阶材料所预期的。我们的计算结果还表明，PZO中的电卡效应分别具有约+6.5°C的电热和约-4.0°C的电冷，这与实验结果相当。
