Interpretation of Crystal-Field Parameters in the Rare-Earth-Substituted Garnets

Abstract

Crystal‐field parameters of Yb³⁺, Eu³⁺, Tm³⁺, Sm³⁺, Dy³⁺, and Er³⁺ ions in various garnet lattices have been analyzed using a development of the superposition model proposed by Bradbury and Newman. This effects, in principle, the separation of the crystal‐field contributions of the different coordinated O²⁻ ions and determines power laws and the angular distortion near substituted ions. A realistic separation of the contributions to the $\text{n\hspace{0.17em}=\hspace{0.17em}4}$ parameters is obtained even when no allowance is made for local distortion. However, owing to their greater angular sensitivity, the contributions to the $\text{n\hspace{0.17em}=\hspace{0.17em}6}$ parameters can only be separated if local angular distortions of up to 9° are allowed for. Results derived for single‐ligand parameters and power laws are in good accord with theoretical results obtained for other rare‐earth systems.