Abstract

The results of studies of the structure, as well as piezoelectric, and dielectric properties, of lead zirconate-titanate ceramics modified with various concentrations of lanthanum (PLZT) are presented. It is found that with an increase in the La content, the grain size and the average size of the domains increase. The PLZT 12/40/60 samples contain both labyrinthine-like and periodic domains and different lateral sizes ranging from several hundred nanometers to 3 μm in diameter. It is found that with an increase in the size of domains in samples with a high content of lanthanum the signal of the piezoelectric response is enhanced. The fact of the existence of areas on the surface of PLZT x/40/60 ceramics, having an internal bias field, as indicated by the asymmetry along the voltage axis of the residual piezoelectric hysteresis loops, is established. In the PLZT 5/40/60 and PLZT 12/40/60 samples, a significant dispersion of the dielectric constant ε(f) and the maximum tangent of the dielectric loss angle in the frequency range from 10⁵ to 10⁶ Hz are observed. This is due to the presence of ionic relaxation polarization. It is found that the value of the dielectric constant increases markedly with an increase in La, which confirms the appearance of a rigid unipolar state in the grains of the PLZT 12/40/60 ceramics. In the samples under study, at low frequencies of the measuring field, an increase in the dielectric loss tangent is observed, which is related to the contribution of the conductivity to tan δ. The dependences of the dielectric loss factor ε'' on the dielectric constant ε' are plotted. They have the form of Cole–Cole diagrams, which indicates the presence of a spectrum of relaxation times, and it is found that the spectral width in the PLZT 5/40/60 samples is approximately half that in the PLZT 12/40/60 samples.

中文翻译：

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PLZT x/40/60 (x = 5; 12) 陶瓷的介电和压电性能

摘要

介绍了用不同浓度镧 (PLZT) 改性的锆钛酸铅陶瓷的结构、压电和介电性能的研究结果。发现随着La含量的增加，晶粒尺寸和畴的平均尺寸增加。PLZT 12/40/60 样品包含迷宫状和周期性区域以及直径从几百纳米到 3 微米不等的不同横向尺寸。发现随着镧含量高的样品中畴尺寸的增加，压电响应的信号增强。PLZT x表面存在区域的事实建立了具有内部偏置场的/40/60 陶瓷，如沿剩余压电磁滞回线的电压轴的不对称性所示。在 PLZT 5/40/60 和 PLZT 12/40/60 样品中，在 10 ⁵到 10 ⁶的频率范围内，介电常数 ε( f ) 和介电损耗角的最大正切存在显着色散观察到赫兹。这是由于存在离子弛豫极化。发现介电常数值随着 La 的增加而显着增加，这证实了 PLZT 12/40/60 陶瓷晶粒中出现了刚性单极状态。在所研究的样品中，在测量场的低频下，观察到介电损耗角正切增加，这与电导率对 tan δ 的贡献有关。绘制了介电损耗因子 ε'' 对介电常数 ε' 的依赖性。它们具有 Cole-Cole 图的形式，表明存在弛豫时间谱，并且发现 PLZT 5/40/60 样品中的谱宽约为 PLZT 12/40/60 中的一半样品。