A Study of Spin-Hamiltonian Parameters and Defect Structure for Co²⁺ Ion in the Tetragonal Zn²⁺ Site of Ba₂ZnF₆ Crystal

Abstract

The spin-Hamiltonian (SH) parameters (g factors g , g ⊥ and hyperfine structure constants A , A ⊥ ) for the Co 2+ ion in the tetragonal Zn 2+ site of a Ba 2 ZnF 6 crystal are calculated from the secondorder perturbation formulas based on the cluster approach for the SH parameters of 3d 7 ions in tetragonal symmetry with the effective spin S = 1/2. In the calculations, a reduction factor due to the dynamical Jahn-Teller effect is used. The calculated results are in reasonable agreement with the experimental values, suggesting that the dynamical Jahn-Teller effect should be considered here. The defect structure of the Co 2+ center in Ba 2 ZnF 6 :Co 2+ is also obtained from the calculations. The results are discussed.