Spectroscopic and crystallographic properties of stoichiometric Na_1-xTa_1-xEu_2xO₃ solid solution

Abstract

In this paper, the NaTa0₃-Eu₂0₃ solid solution has been characterized by x-ray powder diffraction and density measurements. It shows to exist over a very limited range of europium concentration, with a general formula Na_lxTa_lxEu_2x0₃ (0 ≤ x ≤ 0.02). Within the range of compositions of the solid solutions, the optical properties (emission and excitation spectra) of our powder samples were also analyzed, and the results are in good agreement with the proposed mechanism for the europium substitution Na⁺ + Ta⁵⁺ ↔ 2Eu³⁺, where the Eu³⁺ ions enter the sodium sites as well as the tantalate positions in the lattice of NaTa0³.