Among the class of ferroelectric crystals, the lithium-niobate-tantalate (LiNbTaO) system attracts growing attention for applications in the field of nonlinear optics, functional electronics and piezoelectrics. The self-diffusion of the ionic constituents, especially Li, is important for the overall electric conductivity. The aim of this investigation is to figure out how Li diffusion in lithium niobate-tantalate solid solution crystals behaves as a function of the Ta content. Specially grown LiNbTaO single crystals with different niobium to tantalum ratios are used for this purpose. Li tracer self-diffusion is analysed using secondary ion mass spectrometry after applying an isotope-enriched LiNbO tracer layer and subsequent annealing. All investigations are carried out at 250 and 600 °C, respectively. Despite of the theoretically predicted non-linear variation of the volume of the unit cell between the values of the end compounds, the results indicate no significant modification of Li diffusivities within error limits in the whole solid solution range.

中文翻译：

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铌酸锂-钽酸盐固溶体中的锂扩散

在铁电晶体中，铌酸锂（LiNbTaO）系统在非线性光学、功能电子和压电领域的应用日益受到关注。离子成分（尤其是锂）的自扩散对于整体电导率非常重要。本研究的目的是弄清楚锂在铌酸锂-钽酸盐固溶体晶体中的扩散如何随 Ta 含量变化。为此目的，使用了具有不同铌钽比例的特殊生长的 LiNbTaO 单晶。在应用富含同位素的 LiNbO 示踪层并随后退火后，使用二次离子质谱分析 Li 示踪剂自扩散。所有研究分别在 250 和 600 °C 下进行。尽管理论上预测最终化合物值之间晶胞体积的非线性变化，但结果表明在整个固溶体范围内，Li扩散率在误差限度内没有显着变化。