The evolution mechanism of defect dipoles and high strain in MnO2-doped KNN lead-free ceramics
The evolution mechanism of defect dipoles and high strain in MnO2-doped KNN lead-free ceramics
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DOI：
10.1063/1.4948305
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发表时间：
2016-04
影响因子：
4
通讯作者：
Zhihao Zhao;Yejing Dai;Xiaolei Li;Zhe Zhao;Xiaowen Zhang
中科院分区：
文献类型：
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作者：
Zhihao Zhao;Yejing Dai;Xiaolei Li;Zhe Zhao;Xiaowen Zhang
受主掺杂（K0.5Na0.5）NbO 3基陶瓷中的缺陷偶极子对其电学性能有重要影响。本研究探讨了烧结气氛对MnO 2掺杂（K0.5Na0.5）NbO 3的电性能的影响。在Ar气氛中烧结的极化和老化样品描绘了与缺陷偶极子（Mn 2 +Nb <$−VO··）′形成相关的不寻常行为，其在具有较大极性的极化方向上排列。极化和老化的MnO 2掺杂的（K0.5Na0.5）NbO 3陶瓷在Ar气氛中烧结的S-E环显示在极化方向上的应变较大，并在相反的方向上的抑制应变。此外，观察到在3.5kV/mm下单极电应变可以达到0.28%（d33* = 800 pm/V），该值比在空气气氛中获得的值（0.05%）高近5.6倍。这种基于烧结气氛和工艺控制的方法提供了一种有前途的方法，以获得大量的电应变值，适用于高性能的应用。
Defect dipoles in acceptor-doped (K0.5Na0.5)NbO3-based ceramics have a significant influence on their electrical properties. The present study examined the influence of the sintering atmosphere on the electrical properties of MnO2-doped (K0.5Na0.5)NbO3. The poled and aged samples sintered in the Ar atmosphere depicted unusual behavior related to the formation of defect dipoles (Mn2+Nb‴−VO··)′, aligned in the poling direction having larger polarity. The S-E loop of the poled and aged MnO2-doped (K0.5Na0.5)NbO3 ceramics sintered in the Ar atmosphere revealed larger strains in the poling direction and restrained strains in the opposite direction. Furthermore, it is observed that the unipolar electro-strain could reach 0.28% (d33* = 800 pm/V) at 3.5 kV/mm, a value nearly 5.6-fold higher than those obtained in the air atmosphere (0.05%). This method based on the sintering atmosphere and process control provides a promising way to obtain substantial electro-strain values suitable for applications in high-displa...