The influence of temperature on the variation in dielectric nonlinearity and domain structures was investigated for the (Ba_0.95Ca_0.05)(Ti_0.83Zr_0.17)O₃ (BCTZ)-based multilayer ceramic capacitor that shows a diffuse phase transition. Whereas the dielectric constant (ε_r) vs temperature shows a broadened maximum peak at low ac driving field, such a peaked behavior disappears at high ac driving field due to an abrupt increase in dielectric constants at low temperatures. Such low temperature effect can be associated with an enhanced spontaneous polarization (P_S) and a significant increase in irreversible domain wall contribution to polarization representing normal ferroelectric behavior based on the Preisach analysis. No ferroelectric domain contrasts were observed at room temperature through transmission electron microscopy. However, they appeared and became more and more distinct with the decrease in temperature, and the crystal structure also changed from cubic to rhombohedral with increased lattice constants. It demonstrates that the dramatic increase in the dielectric nonlinearity with decreasing temperatures originates from the corresponding changes in domain and crystal structure, where the polar-micro-regions of BCTZ at room temperature change to normal ferroelectric domains at low temperatures.

中文翻译：

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（Ba0.95Ca0.05）（Ti0.83Zr0.17）O3基多层陶瓷电容器的介电非线性行为

对于（Ba _0.95 Ca _0.05）（Ti _0.83 Zr _0.17）O ₃（BCTZ）基多层陶瓷电容器，研究了温度对介电非线性和畴结构变化的影响，该陶瓷电容器具有扩散相变。尽管介电常数（_εr）与温度的关系在低交流驱动场下显示出一个最大的峰值，但由于低温下介电常数的突然增加，这种峰值行为在高交流驱动场下消失了。这种低温效应可能与自发极化增强（P _S），并且根据Preisach分析，不可逆畴壁对极化的贡献显着增加，代表正常的铁电行为。通过透射电子显微镜在室温下未观察到铁电畴对比。然而，随着温度的降低，它们出现并变得越来越明显，并且晶体结构也从立方变为菱面体，晶格常数增加。它表明，介电非线性随着温度的降低而急剧增加，起因于畴和晶体结构的相应变化，其中，室温下BCTZ的极性微区变为低温下的正常铁电畴。