(Li,Na,K)NbO3-based multilayered piezoceramics were characterized by performing unipolar polarization electric field measurements and impedance spectroscopy. Subjecting an as-poled sample to up to 107 cycles in an applied 4 kV mm−1 unipolar cyclic field at 100 °C reduced its polarization by 8.9%. The impedance spectra of as-sintered, as-poled, and fatigued samples were acquired and analyzed. Two relaxation processes reported to occur in single-layered (Na,K)NbO3-based ceramics were identified. They occurred at inner domains and interfaces, including domain walls (DWs) and grain boundaries, below the Curie temperature (T C, 450 °C). The electrical properties of the samples were evaluated by two resistance-constant phase element (2 R-CPE) equivalent circuit analysis. The results indicated that DW pinning was the primary cause of unipolar fatigue.

中文翻译：

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(Li,Na,K)NbO3 基多层压电陶瓷的循环特性和阻抗分析

(Li,Na,K)NbO3 基多层压电陶瓷通过单极极化电场测量和阻抗谱表征。在 100 °C 的 4 kV mm-1 单极循环场中对极化样品进行多达 107 次循环后，其极化降低了 8.9%。获取并分析了烧结态、极化态和疲劳态样品的阻抗谱。确定了在单层 (Na,K)NbO3 基陶瓷中发生的两种弛豫过程。它们发生在居里温度 (TC, 450 °C) 以下的内畴和界面，包括畴壁 (DW) 和晶界。样品的电性能通过两个电阻常数相位元件（2 R-CPE）等效电路分析进行评估。结果表明，DW 钉扎是单极疲劳的主要原因。