Rapid synthesis and structural analysis of Li-Nb-Ti-O solid solutions with superstructure by millimeter-wave heating

Abstract

We have succeeded in synthesizing Li1+x-yNb 1-x-3yTix+4yO3 solid solutions (0.11 ≤ x ≤ 0.18, 0 ≤ y ≤ 0.09) having a superstructure by millimeter-wave heating for only 1 h. Synthesizing temperatures were attempted in the range from 873 to 1273 K. A homogeneous LNT solid solution with a superstructure was formed above 1173 K. Such LNT solid solutions were characterized using X-ray diffraction, a scanning electron microscope, and a transmission electron microscope (TEM) from micro-scale to nano-scale. Element analysis revealed that the superstructure was formed by periodical insertion of intergrowth layers with a high concentration of Ti ions. The structural stability of the LNTsolid solution was estimated by a first-principles calculation. The results revealed that the structure was stable due to the formation of the superstructure, which is composed through an anisotropic arrangement of the Ti ions. © 2011 The Ceramic Society of Japan.