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

The effects of Sr2ZrTiO6 (SZT) addition on the piezoelectric properties of (1 - x)Bi-0.5(Na0.8K0.2)(0.5)TiO3 (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 degrees 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 (d(33)), it was increased by SZT addition in the MPB region (x = 0-0.01) and the highest d(33) 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 d*(33) = 436pm/V was obtained at the composition of x = 0.02. (C) 2017 The Japan Society of Applied Physics