Mechanisms Underlying the Formation of Defect Complexes in LiNbO3:Mg(5.05 mol %):Fe(0.009 mol %) Doubly Doped Crystals

Abstract

The IR absorption spectrum of LiNbO₃:Mg(5.05 mol %):Fe(0.009 mol %) crystals has been shown to be noticeably shifted (by ~50 cm^–1) to higher frequencies, corresponding to stretching vibrations of OH^– groups, in comparison with the spectrum of congruent LiNbO₃ crystals. Analysis has shown that the shift is due to the formation of \({\text{Mg}}_{{{\text{Li}}}}^{ + }\)–\({\text{Fe}}_{{{\text{Nb}}}}^{{2 - }}\)–OH^– and \({\text{Mg}}_{{{\text{Li}}}}^{ + }\)–\({\text{Mg}}_{{{\text{Nb}}}}^{{3 - }}\)–ОН^– defect complexes.