Electrical Properties of Ag-Doped 0.94(K_0.5Na_0.5)NbO₃-0.06LiNbO₃ Ceramics Prepared by Templated Grain Growth

Abstract

In this study, we have investigated the current-voltage characteristics of Ag_-doped 0.94(K_0.5Na_0.5)NbO₃-0.06LiNbO₃ lead-free piezoelectric ceramics, prepared by a template grain growth (TGG) method employing cubic (K,Na)NbO₃ single crystal seeds as templates. It is well known that TGG methods can improve piezoelectric properties by increasing the grain size during the sintering process. The X-ray diffraction of the sample at room temperature showed perovskite structure. Scanning electron microscopy (SEM) showed great differences in both grain shape and size between the TGG-processed ceramic and the conventionally prepared ceramic. The leakage current density of Ag_-doped 0.94(K_0.5Na_0.5)NbO₃-0.06LiNbO₃ ceramic prepared by the TGG process was reduced. The current-voltage characteristics according to varying temperature provide us with the temperature-dependent resistance and temperature coefficient of resistance in the ceramics prepared in this study. The true leakage currents and different types of dipole motions of the ceramic are also discussed.

Keywords:

• Templated grain growth
• KNN-LN
• electrical properties

Acknowledgments

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), which was funded by the Ministry of Education, Science and Technology (grant number 2010-0011536) and the National Research Foundation of Korea (NRF) grant funded by the Korea goverment (MEST) (No. 2011-0029625).