Piezoelectric Properties and Local Structure Analysis of (Na_0.5K_0.45Li_0.05)NbO₃ Solid Solutions by Malic Acid Complex Solution Method

Abstract

(Na_0.50K_0.45Li_0.05)NbO₃ (NKLN) powder was synthesized by the malic acid complex solution method, and NKLN solid solutions were then fabricated at firing temperatures of 900−1050℃ using a conventional solid-state reaction technique. The piezoelectric properties of the resulting materials were measured, and samples produced at 950℃ were found to exhibit the maximum d₃₃ and k_p values of 151 pC/N and 32%, respectively. On the basis of a local structural analysis using high-energy X-ray diffraction, the distortion of NbO₆ octahedra, which is the origin of the ferroelectric properties, also exhibited a maximum at 950℃. Thus, this is the optimal firing temperature for fabricating NKLN samples with excellent piezoelectric properties and the largest NbO₆ octahedral distortion.