Effects of TiO sub 2 addition to LiNbO sub 3 on the cation vacancy content, Curie temperature, and lattice constants.

The defect model of Abrahams and Marsh is expanded to consider the addition of TiO sub 2 and other oxides to form solid solutions with both the stoichiometric and congruent compositions of LiNbO sub 3. DTA measurements were made for several additions of TiO sub 2 to both the stoichiometric and congruent compositions in order to determine their Curie temperatures, T sub c. It is shown that T sub c and the limits of solubility are determined by the cation vacancy content regardless of whether these are formed by Li deficiency or by the presence of aliovalent ions.