Effect of Antimony Concentration on the Crystalline Structure, Dielectric, and Piezoelectric Properties of (Na0.5K0.5)0.945Li0.055Nb1−xSbxO3 Solid Solutions

The effect of antimony concentration on the piezoelectric properties of (Na0.5K0.5)0.945Li0.055Nb1−xSbxO3 was examined for 0≤x≤0.1. The piezoelectric coefficients exhibited a maximum, d33=240 pC/N and d31=−82 pC/N at x=0.04, coinciding with the maximum of the grain size and the apparent density at x=0.04. The grain size, the apparent density, and the piezoelectric coefficients decreased with an increasing x at higher x likely due to the onset of a Sb‐rich second phase. The weight fraction of the tetragonal phase increased with an increasing x to almost unity at x=0.1, likely also contributing to the decrease in the piezoelectric coefficients at higher x.