Depolarization Temperature Shift Of Li_(0.08)na_(0.92)nbo_3 Lead-free Piezoelectric Ceramics By High-electric-field Poling

摘要

The increase in depolarization temperature induced by the poling of (Li_xNa_(1-x))NbO_3 ceramics having an Li concentration of x = 0.08 (LNN8) was studied. Initially, the Curie temperature T_C was measured to be approximately 300 ℃, and it increased after the application of poling at high electric fields; this increase in Curie temperature depended on the poling conditions employed. When poling was performed at 120 ℃ at an electric field of 5 kV/mm for 5 min, there was no change in T_C and the depolarization temperature was slightly lower than T_C. However, both these temperatures increased up on poling at a higher electric field. The X-ray diffraction patterns obtained suggested that the domain volumes of the ceramics were altered by poling at a high electric field and that this structural change caused a change in depolarization temperature.