Preparation and properties of LiTaO3-based solid solutions with cation vacancies

It has been found that nonstoichiometric solid solutions (Li1−xM2+x2□x2)TaO3 with M=Zn, Ni, Mg and Ca exist over wide ranges. In the case of the Zn-system, especially, a LiTaO3 structure was still stable even at x=0.5, where 25% of the Li sites are vacant. A new series of solid solutions shows ferroelectric properties. The Curie temperature is closely related with the axial ratio c/a of the hexagonal cell.