材料期刊网

This paper reports the theoretical calculations of spin-Hamiltonian (SH) parameters (g factors g(parallel to) and g perpendicular to and hyperfine structure constants A(parallel to) and A(perpendicular to)) for the approximately tetragonal Co(2+) center in Na(2)MgAlF(7):Co(2+) crystals from the second-order perturbation formulas based on the cluster approach for d(7) ions in tetragonal octahedra with the effective spin S = 1/2. In the calculations, the reduction in the spin-orbit parameters and the orbital reduction factors due to the dynamical Jahn-Teller effect is considered. The calculated SH parameters are in agreement with the experimental values. The defect structure of the Co(2+) center, which is consistent with the expectation based on the size of the impurity of the Co(2+), and that of the replaced Mg(2+), is obtained from the calculations. The results are discussed.