A new rutile structure solid solution phase in the LiNb(3)O (8)-TiO(2) system, and its role in Ti diffusion into LiNbO (3).

An extensive range of solid solubility was found in the LiNb (3)O(8)- TiO(2) system. The solid solution phase has the undistorted rutile structure for 0.40=x=1.0 in (Li(0.25)Nb(0.75)O(2)) (1-x)(TiO(2))x. A member of this series, with x=0.59, is proposed to be the intermediate phase formed during Ti indiffusion in LiNbO(3) during optical waveguide formation, rather than Ti (0.65)Nb(0.35)O(2) as was previously postulated. This assignment agrees with the experimental results of previous studies of Ti indiffusion into LiNbO(3) single crystals, and is consistent with a Ti diffusion mechanism based on defect chemistry studies. The preparation and structural characterization of the LiNb (3)O(8)-TiO(2) solid solution phase is discussed.