The g Factors and Defect Structure of Orthorhombic Dy3+ Ions in CdF2 Crystals

Abstract

The electronic paramagnetic resonance g factors gx, gy and gz of an orthorhombic Dy3+ center in CdF2 are studied by the perturbation formulae of the g factors for a 4f9 ion in orthorhombic symmetry. In these formulae, the contributions to g factors due to J-mixing among the ground 6H15/2, the first excited 6H13/2 and the second excited 6H11/2 states via crystal-field interaction, lead to admixtures among the states with the same J-value via spin-orbit coupling. In addition, the admixtures between the lowest Kramers doublet Γγ and other 20 Kramers doublets Γ x within the states 6HJ (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 Δ Z ≈ 0.272 Å.