Relationship between crystal structure and ferroelectric properties in Bi_0.5−0.5<i>_x</i>Na_0.5−0.5<i>_x</i>Sr<i>_x</i>Ti₁₋<i>_x</i>Zr<i>_x</i>O₃ ceramics

Abstract

The crystal structure, piezoelectric and ferroelectric properties of the Bi0.5−0.5xNa0.5−0.5xSrxTi1−xZrxO3 (BNSTZ) ceramics were characterized in this study. From the variations in the lattice parameters, the solubility limit of the BNSTZ ceramics was determined to be x = 0.075. The crystal structure refinement revealed that the distortion of (Bi, Na and Sr)O12 polyhedron decrease with increasing x and such the variation in the distortion exerts an influence on the decrease in remnant polarization from 35 to 28 µC/cm2. Although the slight shifts of the depolarization temperature (Td) and rhombohedral-tetragonal phase transition temperature (TR-T) to lower temperature were recognized, it suggested that the shift of Td is predominant for the increase in dielectric constant at room temperature which leads to the enhancement of the d33 value. As a result, the d33 and kp values were 85 pC/N and 18.7%, respectively at x = 0. 075.