The g factors and defect structure of orthorhombic Dy3+ ions in CdF2 crystals

The electronic paramagnetic resonance g factors g(x), g(y), and g(z) of an orthorhombic Dy3+ center in CdF2 are studied by the perturbation formulae of the g factors for a 4f(9) ion in orthorhombic symmetry. In these formulae, the contributions g factors due to J-mixing among the ground H-6(15/2), the first excited H-6(13/2) and the second excited H-6(11/2) states vi a crystal-field interaction, lead toad mixtures among the states with the same J-value via spin-orbit coupling. In addition, the admixtures between the lowest Kramers doublet Gamma gamma and other 20 Kramers doublets Gamma x within the states 6H(J) (J = 15/2. 13/2 and 11/2) via crystal-field and orbital angular momentum interactions are considered. In the above orthorhombic center, the impurity Dy3+ is associated with co-doped crystals with alkali metal ions in the [110] axis. By analyzing the g factors, we find that the impurity Dy3+ ion does not reside in the ideal Cd2+ site but moves towards the co-doped alkali metal ion along the [110] direction by a displacement Delta Z approximate to 0.272 angstrom.