The H+ related defects in near-stoichiometric lithium niobate crystals investigated by domain reversal

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 infrared absorption spectra. It is found that the position and halfwidth 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 is introduced. In this model, the four Li vacancies, charge-compensating an anti-site Nb5+ ion (Nb-Li(4+)), occupy two types of lattice positions: three of them at the nearest Li-sites Nb-Li(4+) and the other one at a nearer Li-site above the same oxygen plane with Nb-Li(4+) (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.