材料期刊网

The spin Hamiltonian parameters anisotropic g factors g(\\), g(perpendicular to) and hyperfine structure constants A(\\) and A I, as well as the local structure of the trigonal Co2+ center in Bi4Ge3O12 (BGO) are theoretically investigated by the perturbation formulas of the spin Hamiltonian parameters for a V ion in trigonal symmetry, based on the cluster approach. It is found that the impurity Co2+ substituting the host Bi3+ undergoes an off-center displacement DeltaZ(approximate to -0.132 Angstrom) away from the center of the oxygen octahedron along the C-3 axis. The spin Hamiltonian parameters based on the above displacement show reasonable agreement with the observed values. The results are discussed.