Transport and Electromechanical Properties of Ca_3TaGa_3Si_2O_14 Piezoelectric Crystals at Extreme Temperatures
Transport and Electromechanical Properties of Ca_3TaGa_3Si_2O_14 Piezoelectric Crystals at Extreme Temperatures
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DOI：
10.1557/adv.2019.16
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发表时间：
2019-01
期刊：
影响因子：
0.8
通讯作者：
Y. Suhak;W. Johnson;A. Sotnikov;H. Schmidt;H. Fritze
中科院分区：
文献类型：
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作者：
Y. Suhak;W. Johnson;A. Sotnikov;H. Schmidt;H. Fritze
利用同位素^18O作为示踪剂，并利用二次离子质谱（西姆斯）分析了结构有序的压电Ca_3TaGa_3Si_2O_14（CTGS）单晶在1000-1300 °C温度范围内的输运机制。确定的氧自扩散系数，使计算的氧离子对总电导率的贡献，这被证明是小的。由于预期阳离子的贡献非常低，因此总电导率必须由电子传输主导。离子电导率和电子电导率由不同的机制控制，激活能分别为（1.9±0.1）eV和（1.2±0.07）eV。此外，机电损耗作为温度的函数进行了研究，通过对样品的阻抗谱电极和非接触式音串激励技术。在高于650 °C的温度下，与电导率相关的损失占主导地位。最后，CTGS谐振器的操作证明在低温和材料的压电应变常数确定从4.2 K到室温。
Transport mechanisms in structurally ordered piezoelectric Ca_3TaGa_3Si_2O_14 (CTGS) single crystals are studied in the temperature range of 1000-1300 °C by application of the isotope ^18O as a tracer and subsequent analysis of diffusion profiles of this isotope using secondary ion mass spectrometry (SIMS). Determined oxygen self-diffusion coefficients enable calculation of oxygen ion contribution to the total conductivity, which is shown to be small. Since very low contributions of the cations have to be expected, the total conductivity must be dominated by electron transport. Ion and electron conductivities are governed by different mechanisms with activation energies (1.9±0.1) eV and (1.2±0.07) eV, respectively. Further, the electromechanical losses are studied as a function of temperature by means of impedance spectroscopy on samples with electrodes and a contactless tone-burst excitation technique. At temperatures above 650 °C the conductivity-related losses are dominant. Finally, the operation of CTGS resonators is demonstrated at cryogenic temperatures and materials piezoelectric strain constants are determined from 4.2 K to room temperature.