Defect chemistry of Sr site nonstoichiometry in Sr_xTi_0.985(Nb_2/3Zn_1/3)_0.015O₃ ceramics and the resulting effects on the structure and dielectric behavior are systematically investigated by experiment and density functional theory (DFT) methods. The results indicate that, appropriate Sr deficiency benefits the dielectric properties and grain growth due to the creation of Sr vacancy. While Sr excess deteriorates the dielectric properties and inhibits the grain growth by forming a Ruddlesden‐Popper structure. In Sr‐deficient sample, more point defects arise and aggregate into defect clusters, resulting in great changes in local structures and the enhancement of dielectric properties. The Sr vacancy benefits the generation of oxygen vacancy, thus facilitating the localization of electrons and the decrease in dielectric loss. Besides, the electronic polarization and structural polarization are also improved by Sr vacancy and the resultant oxygen vacancy, leading to the further enhanced dielectric properties. These findings may facilitate the development of defect engineering towards novel multifunctional electronic materials.

中文翻译：

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SrxTi0.985（Nb2 / 3Zn1 / 3）0.015O3陶瓷中A位非化学计量的缺陷化学及所得的介电行为

Sr _x Ti _0.985（Nb _2/3 Zn _1/3）_0.015 O ₃中Sr位置非化学计量的缺陷化学通过实验和密度泛函理论（DFT）方法，系统地研究了陶瓷及其对结构和介电性能的影响。结果表明，由于Sr空位的产生，适当的Sr缺乏有利于介电性能和晶粒生长。而过量的锶会通过形成Ruddlesden-Popper结构而降低介电性能并抑制晶粒长大。在Sr不足的样品中，会出现更多的点缺陷并将其聚集到缺陷簇中，从而导致局部结构发生巨大变化并提高介电性能。Sr空位有利于氧空位的产生，因此有利于电子的定位和介电损耗的降低。除了，Sr空位和由此产生的氧空位也改善了电子极化和结构极化，从而进一步提高了介电性能。这些发现可能有助于缺陷工程向新型多功能电子材料的发展。