Effects of Structural Factors on Piezoelectric Performance of Lead-free Perovskite Compounds

Abstract

Three powders with compositions close to 0.98(Na_0.50K_0.45Li_0.05)NbO₃−0.02Ca(Zr_0.5Ti_0.5)O₃ (NKLN−CZT) were synthesized using a malic acid complex solution method, and three solid solutions were then fabricated using a conventional solid-state reaction technique. The optimal substitutional Ta content and Zr/Ti ratio for NKLN−CZT were examined by measuring the piezoelectric properties. Based on the results, a 0.98(Na_0.50K_0.45Li_0.05)(Nb_0.98Ta_0.02)O₃−0.02Ca(Zr_0.4Ti_0.6)O₃ solid solution was fabricated to clarify the synergistic effect when the optimal values for both these parameters were used. The resulting material was found to exhibit the maximum longitudinal piezoelectric coefficient of 240 pC/N and radial electromechanical coupling factor of 41%. On the basis of these results and those for the average and local structure obtained using high-energy X-ray diffraction, this compound has potential as a high-Curie-temperature, high-performance, lead-free piezoelectric material.