Synthesis and piezoelectric properties of (1 − x)Bi0.5(Na0.8K0.2)0.5TiO3–xSr2ZrTiO6 ceramics

Abstract

The effects of Sr2ZrTiO6 (SZT) addition on the piezoelectric properties of (1 − x)Bi0.5(Na0.8K0.2)0.5TiO3 (BNKT)–xSZT ceramics were characterized in this study. The X-ray powder diffraction (XRPD) profiles and Raman spectra of the ceramics in the composition range of 0–0.02 implies the presence of morphotropic phase boundary (MPB) which consists of the rhombohedral and tetragonal phases. Moreover, the temperature dependence of dielectric loss indicated a presence of the ferroelectric–relaxor transition temperature (TF–R) of around 75 °C for x = 0.005 and the temperature dependence shifted to a lower temperature at x = 0.01. The temperature dependence of the P–E hysteresis loop of the ceramics at the compositions of x = 0.005–0.02 showed pinched hysteresis loops above TF–R. Regarding the piezoelectric constant (d33), it was increased by SZT addition in the MPB region (x = 0–0.01) and the highest d33 of 202 pC/N was obtained at the composition of x = 0.0025. The S–E unipolar loop was also evaluated, the strain of the ceramic increased up to x = 0.02; and the highest pm/V was obtained at the composition of x = 0.02.