Optical properties of Li_1−xNb_1−xEu_2xO₃solid solutions

Abstract

Abstract The effects of europium substitution on crystalline solubility, structural changes and optical properties of LiNbO3 is reported. Li1−xNb1−xEu2xO3 solid solutions exist over a very limited range of europium concentrations (x ≤ 0.01). The solid solutions were characterized by X-ray powder diffraction and density measurements. Within the range of compositions of the solid solutions, the optical properties (emission and excitation spectra) of the Eu3+ ions have been characterized. The obtained optical data indicate that two equally abundant europium luminescent species exist in the stoichiometric speciments; these correspond to the Eu3+ ions occupying the Li+ and Nb5+ sites, in agreement with the replacement mechanism which is inferred from density measurements. Other Eu3+ luminescent species which appear to be closely related with lithium deficiency were found to exist in nonstoichiometric samples, in addition to those which are present in the stoichiometric materials.