Interrelation of intrinsic and extrinsic defects - congruent, stoichiometric, and regularly ordered lithium niobate

NMR Analysis of Mg Ion Localization in LiNbO3Crystal

“…These results are in good agreement with the assumption that at the MgO concentration in the melt up to threshold, Mg 2+ ions firstly occupy positions of Li + -ions preventing the appearance of antisite Nb Li ions. Nevertheless, it should be noted that the angular dependence of the NMR linewidth of the 93 Nb central transition for the samples doped with 5% MgO and 7% MgO, obtained by us for the angular band |θ| ≤ 15 • , strongly differs from the known data [24].…”

“…[24] the additional broadening of the 93 Nb NMR lines in LiNbO 3 :Mg crystals can be explained by increasing the deviations of EFG tensor parameters (especially -C z and EFG asymmetry parameter values, as well as increasing the EFG tensor principal axis off--orientation on 93 Nb nuclei). However, our results show that the additional broadening of 93 Nb NMR line is connected primarily with the increase of dispersion of C z value distribution on 93 Nb nuclei sites, which is the indirect evidence of the existence of (Mg Li −V Li ) defect complexes formed in the crystal structure.…”

“…It should be noted that the results obtained by 93 Nb NMR investigation on a single LN crystals doped with 4.5% MgO [24] are in contradiction to cited above [23]. It has been shown [23] that the linewidth of (−1/2 ↔ +1/2) transition of 93 Nb NMR spectrum in the sample doped with 4.5% MgO is essentially higher (up to 5 times) than in nominally pure congruent LN crystal for all the range of crystal orientations in magnetic field.…”

Dielectric properties of lithium niobate–tantalate crystals

“…Its crystal structure [3,4] and defect structure [5,6] have attracted considerable interest these years. Recent improvements have been achieved in the field of holographic storage where two-color [7] and twocenter redording [8] have been developed.…”

“…Lithium niobate is a slightly nonstoichiometric, typically Li-deficient crystal, preferably grown at the congruently melting composition with 48. 5 [5,6]. From the viewpoint of the synthetic chemistry, the dopant usually prefers to occupy the vacant lattice site in the host.…”