EPR and optical spectroscopy of Yb3+ ions in hexagonal perovskite RbMgF3 crystals

EPR and optical spectroscopy of trigonal Yb3+ centers in RbMgF3 are reported. The results of these experiments make it possible to conclude that Yb3+ ions replace Mg2+ host cations at two different sites forming three different types of paramagnetic centers. The empirical schemes of the energy levels for trigonal paramagnetic centers of Yb3+ ions have been established and parameters of the corresponding crystal fields have been determined. Structural models of the observed centers are proposed.