EPR and optical spectroscopy of Yb3+ ions in LiCaAlF6 single crystals

Abstract EPR and optical spectroscopy of trigonal Yb3+ centers in LiCaAlF6 are reported. The results of these experiments make it possible to conclude that Yb3+ ions replace host cation sites Ca2+ forming mainly one type of paramagnetic center of trigonal symmetry. Positions of lines in optical spectra were specified of the observed center. The crystal field parameters of trigonal center Yb3+ were determined. Structural models of the observed center are proposed. It is shown that the substitution of the Yb3+ ion for the Ca2+ ion leads to the considerable compression of the YbF6 octahedron along the trigonal axis of the center.