Li Weixiong, Chen Chunxu, Xie Guangzhong, Su Yuanjie
State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China (UESTC), Chengdu 610054, China.
Nanomaterials (Basel). 2021 Jul 5;11(7):1753. doi: 10.3390/nano11071753.
KNaNbO is considered as one of the most promising lead-free piezoelectric ceramics in the field of wearable electronics because of its excellent piezoelectric properties and environmental friendliness. In this work, the temperature-dependent longitudinal piezoelectric coefficient d33* was investigated in KNaNbO single crystals via the Landau-Ginzburg-Devonshire theory. Results show that the piezoelectric anisotropy varies with the temperature and the maximum of d33max* deviates from the polar direction of the ferroelectric phase. In the tetragonal phase, d33maxt* parallels with cubic polarization direction near the tetragonal-cubic transition region, and then gradually switches toward the nonpolar direction with decreasing temperatures. The maximum of d33o* in the orthorhombic phase reveals a distinct varying trend in different crystal planes. As for the rhombohedral phase, slight fluctuation of the maximum of d33r* was observed and delivered a more stable temperature-dependent maximum d33maxr* and its corresponding angle in comparison with tetragonal and orthorhombic phases. This work not only sheds some light on the temperature-dependent phase transitions, but also paves the way for the optimization of piezoelectric properties in piezoelectric materials and devices.
由于具有优异的压电性能和环境友好性，KNaNbO被认为是可穿戴电子领域最有前途的无铅压电陶瓷之一。在这项工作中，通过朗道-金兹堡-德文希尔理论研究了KNaNbO单晶中随温度变化的纵向压电系数d33*。结果表明，压电各向异性随温度变化，d33max的最大值偏离铁电相的极化方向。在四方相中，d33maxt在四方-立方转变区域附近与立方极化方向平行，然后随着温度降低逐渐转向非极化方向。正交相中d33o的最大值在不同晶面呈现出明显不同的变化趋势。对于菱方相，观察到d33r最大值的轻微波动，并且与四方相和正交相相比，给出了更稳定的随温度变化的最大d33maxr*及其相应角度。这项工作不仅揭示了随温度变化的相变，也为优化压电材料和器件的压电性能铺平了道路。
Zotero 插件
