Domain reversal and heat treatment were carried out on near-stoichiometric lithium niobate crystals and H+ related defect structure of this crystal was studied through infra-red absorption spectra. It was found that the position and half-width of some deconvoluted peaks of absorption band change apparently during domain reversal and heat treatment. According to these experimental results, a more suitable model about the location of Li-vacancy in LiNbO3 was introduced. In this model, the four Li vacancies, charge-compensating an anti-site Nb5+ ion (NbLi4+), occupy two types of lattice positions: three of them at the nearest Li-sites NbLi4+ and the other one at a nearer Li-site above the same O plane with NbLi4+.

The H+ Related Defects in Near-Stoichiometric Lithium Niobate Crystals Investigated by Domain Reversal. W.Yan, Y.Kong, L.Shi, X.Xie, X.Li, J.Xu, C.Lou, H.Liu, W.Zhang, G.Zhang: Physica Status Solidi A, 2004, 201[9], 2013-20