Influence of Adsorbate-Induced Charge Screening, Depolarization Factor, Mobile Carrier Concentration, and Defect-Induced Microstrain on the Size Effect of a BaTiO3 Nanoparticle
Influence of Adsorbate-Induced Charge Screening, Depolarization Factor, Mobile Carrier Concentration, and Defect-Induced Microstrain on the Size Effect of a BaTiO3 Nanoparticle
复制标题
DOI：
10.1021/jp312609j
复制
发表时间：
2013-09
影响因子：
3.7
通讯作者：
K. Yasui;K. Kato
中科院分区：
文献类型：
--
作者：
K. Yasui;K. Kato
据实验报道，当室温下晶体尺寸小于临界尺寸时，BaTiO 3单晶的晶体结构变为立方，而宏观BaTiO 3单晶的晶体结构为四方晶系。然而，对于范围从约5至200 nm的不同实验，临界尺寸有很大不同。在本文中，自由能的数值计算已经进行了研究的机制，在BaTiO 3单晶的临界尺寸的大的差异。结果表明，由于退极化能降低，临界尺寸随着吸附物诱导电荷屏蔽程度的增加而显著减小。此外，较高的移动载流子浓度的颗粒，以及较小的去极化因子和较小的缺陷引起的微应变显着降低的临界尺寸。此外，还提出了在30nm以上的颗粒尺寸中，90°畴结构是不稳定的，而在30nm以上的颗粒尺寸中，90°畴结构是稳定的。
It has been experimentally reported that the crystal structure of a BaTiO3 single crystal becomes cubic when the crystal size is smaller than a critical one at room temperature, while the crystal structure of the macroscopic BaTiO3 single crystal is tetragonal. The critical size is, however, largely different for different experiments ranging from about 5 to 200 nm. In the present paper, numerical calculations of the free energy have been performed to study the mechanism of the large diversity in the critical size of a BaTiO3 single crystal. The results have indicated that the critical size becomes considerably smaller as the degree of adsorbate-induced charge screening increases because the depolarization energy is reduced. In addition, higher mobile-carrier concentration in a particle as well as smaller depolarization factor and smaller defect-induced microstrain considerably decrease the critical size. Furthermore, it is suggested that above about 30 nm in particle size the domain structure with 90° do...