New Lead-Free Relaxor Ferroelectrics Derived from (K_0.5Na_0.5)NbO₃ for High Temperature Applications

Abstract

In order to develop high-temperature lead-free relaxor ferroelectrics, 0.95(K_0.5Na_0.5) NbO_3–0.05Ba(Mg_1/3Nb_2/3)O₃ (0.95KNN–0.05BMN) solid solution was synthesized by conventional solid-state sintering. The diffuse phase transition and the temperature of the maximum dielectric permittivity shifting towards higher temperature with increasing frequency, which are two typical characteristics for relaxor ferroelectrics, were observed in 0.95KNN–0.05BMN solid solution. The dielectric relaxor behavior obeys a modified Curie-Weiss law. The relaxor nature is attributed to the appearance of polar nano-regions. The results indicate that this material is indeed a lead-free relaxor ferroelectric with high T_m (∼200°C), useful for high temperature applications.

Keywords:

• High-temperature
• lead-free
• relaxor ferroelectrics

Acknowledgments

This work was supported by NPU Foundation for Fundamental Research and Chinese National and Shaanxi Provincial Natural Science Foundation (No. 10804130 and No. 60871027).