Peculiarity of O2- and Li+ electrodiffusion into lithium niobate single crystals

Congruently grown LiNbO3 single crystals show both a high oxygen and lithiu m ionic conductivity at temperatures above 500 degreesC. The high oxygen io nic conductivity can be understood in terms of a certain amount of oxygen v acancies already present in congruently as-grown LiNbO3 single crystals. Th e electrocoloration phenomenon in LiNbO3 single crystals is due to a proces s where Lithium ions and electrons are injected by a double charge mechanis m into LiNbO3. Optical and electrical properties of electrocolored LiNbO3 c rystals were investigated. The motion of stoichiometric domains (regions wi th different stoichiometry) through a LiNbO3 crystal from one electrode to the other is studied and described in terms of electrodiffusion of the ions and electrons. (C) 2000 Published by Elsevier Science B.V.