Phase equilibria and curie temperature in the LiNbO3−xTiO2 system, investigated by dta and x-ray diffraction

Abstract Solidus and liquidus temperatures, ferroelectric Curie temperature and lattice parameters of phases in the congruent LiNbO 3 −xTiO 2 system was determined (0 2 phase shows solid solubility in congruent LiNbO 3 up to x = 0.20 at 1187°C. The Curie temperature of the solid solution Li 0.954 Nb 1.0092 O 3 :xTiO 2 decreases substantially with increasing amounts of TiO 2 . This temperature variation was expressed as a function of the equivalent composition Re = 0.954 0.954 + 1.0092 + x ; it coǐncides with the Curie temperature variation of LiNbO 3 with composition, which has also been studied by DTA. Outside the solid solution range (x > 0.20) two phases are present: a LiNbO 3 — type phase and a rutile-type phase.