Structural phase transitions and processes of “order-disorder” in the ferroelectric Li0.12Na0.88TayNb1-yO3 solid solution

Abstract

The system of the LixNa1-xTayNb1-yO3 solid solutions based on sodium niobate with oxygen-octahedral type of structure is of great interest because the changes of the components concentration and the temperature are accompanied by a variety of structural phase transitions. Particularly, the Li0.12Na0.88TayNb1-yO3 solid solution is promising as a material with high superionic conductivity. When х = 0.12 the structure orders in such a way as to make the phase transition to the superionic state possible. Besides, at temperatures 315–350 0С in the Li0.12Na0.88TayNb1-yO3 solid solution the phase transition from ferroelectric to antiferroelectric phase taking place before the superionic one can be observed. They were found at ~ 400÷460 0С.