Cu-Doping-Modified Order State, Ferroelectric Property, Multiscale Inhomogeneities, and Local Structure in the Relaxor KTa1–xNbxO3 Crystal
Cu-Doping-Modified Order State, Ferroelectric Property, Multiscale Inhomogeneities, and Local Structure in the Relaxor KTa1–xNbxO3 Crystal
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DOI：
10.1021/acs.cgd.2c00903
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发表时间：
2022-10
期刊：
影响因子：
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通讯作者：
Jianwei Zhang;XiaoPing D;Jiguang Zhao;Yongsheng Duan;Xiaolei Lv;Xuping Wang;Bing Liu;SiTong Liu;Jixue Zhou;Hang Chen
中科院分区：
文献类型：
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作者：
Jianwei Zhang;XiaoPing D;Jiguang Zhao;Yongsheng Duan;Xiaolei Lv;Xuping Wang;Bing Liu;SiTong Liu;Jixue Zhou;Hang Chen
从介电测量、整体铁电性能、电光调制和局域结构等方面对Cu掺杂KTa_（1-x）Nb_xO_3晶体进行了综合研究。通过Cu掺杂可以稳定畴结构的取向，并且在铁电相中不受热干扰，并且在顺电相中可以降低极性纳米区（PNR）的场驱动活性。矫顽场降低，畴结构反转过程发生明显变化，这分别归因于缺陷偶极子的非均匀性增强和驱动力的作用。KTN和KTN：Cu晶体电光调制深度的频率依赖性表明，Cu掺杂可以增强PNR的多尺度不均匀性和偏振性。基于第一性原理计算，计算了KTN和KTN：Cu的八面体畸变，结果表明Cu掺杂可以导致更大的八面体畸变，从而增强局域非均匀性，导致更强的局域极化。该研究将为晶体的生长提供指导，实现功能材料的优化和设计。
Cu doping in the KTa1–xNbxO3crystal was investigated comprehensively from the dielectric measurement, global ferroelectric property, electro-optic (EO) modulation, and local structure. The orientation of the domain structure can be stabilized by Cu doping and is immune to thermal disturbance in the ferroelectric phase, and the field-driven activity of polar nanoregions (PNRs) can be decreased in the paraelectric phase. The coercive field was reduced and the reversal process of the domain structure was greatly changed, which could be attributed to the enhanced heterogeneity and the driving force provided by the defect dipole, respectively. The frequency dependence of the EO modulation depth for KTN and KTN:Cu crystals implied that Cu doping can strengthen the multiscale inhomogeneity and polarization of PNRs. Based on the first-principles calculation, the octahedral distortions of KTN and KTN:Cu were calculated, and the results implied that Cu doping can result in a greater octahedron distortion, thus enhancing the local heterogeneity and resulting in stronger local polarization. The study will provide guidance for the growth of crystals to realize the optimization and design of functional materials.