Synthesis and Characterization of Li-Modified AgTaO3

摘要

(Li (x) Ag1-x )TaO3 (0 a parts per thousand currency sign x a parts per thousand currency sign 0.15) ceramics were fabricated by a mixed-oxide solid-state sintering route. Compositions with x a parts per thousand currency sign 0.1 sintered into single-phase compounds and could be indexed according to the rhombohedral, or R3c structure. For x > 0.1, x-ray diffraction revealed second-phase formation, probably LiTaO3 and Ag2Ta8O21. It was noticed that the metastable and stable phase solubility limits for Li in AgTaO3 were x < 0.05 and 0.10 < x < 0.15, respectively. Raman and dielectric measurements confirmed the existence of a ferroelectric state in the compositions with x a parts per thousand yen 0.05. This triggering of ferroelectricity supports the premise that substitution of relatively smaller ions increases the displacement of the A-site cation. The transition temperature was found to increase as a function of increasing Li concentration. Low-temperature (< 100 K) Raman spectra and electron diffraction indicated that Li-doped AgTaO3 ceramics seem to adopt new tilt systems.