材料期刊网

Based on the defect model that the rhombic Dy(3+) center in AgCl crystal is formed by substitutional Dy(3+) ion associated with two nearest Ag(+) vacancies (V(Ag)) along the (1 1 0) and ((1) over tilde (1) over tilde 0) axes owing to charge compensation, the spin-Hamiltonian parameters (g factors g(i) and hyperfine structure constants (161)A(i) and (163)A(i), where i=x, y, z) of this rhombic Dy(3+) center are calculated from a diagonalization (of energy matrix) method. In the method, the Zeeman (or magnetic) and hyperfine interaction terms are attached to the classical Hamiltonian used in the calculation of crystal-field energy levels and a 66 x 66 energy matrix concerning this Hamiltonian is constructed by taking all the ground-term multiplets (6)H(J) (J=15/2, 13/2, 11/2, 9/2, 7/2, 5/2) into account. The calculated results (g factors & and average vertical bar A((161)Dy(3+))vertical bar and vertical bar(A) over bar((163)Dy(3+))vertical bar) are in reasonable agreement with the experimental values. From the calculations, the above defect model of rhombic Dy(3+) center is confirmed, the defect structure of this Dy(3+) center (characterized by the displacement of Cl(-) ligand caused by VAg) is obtained and the components of hyperfine structure constants A(i)((161)Dy(3+)) and A(i)((163)Dy(3+)) are predicted. The results are discussed. (c) 2010 Elsevier B.V. All rights reserved.