The defect models of 2 trigonal Ti3+ centers in the LaMgAl11O19:Ti3+ (LMA:Ti3+) crystal were suggested as center 1 at the 2a site and center 3 at the 4f site. By using the crystal field parameters Dq based on the suggestion, the g-factors for both Ti3+ centers were calculated from 2 microscopic spin-Hamiltonian theory methods, the complete diagonalization (of the energy matrix) method (CDM) and the perturbation theory method, based on the 2 spin-orbit parameter model (where both the contribution to spin-Hamiltonian parameters from the spin-orbit coupling parameter of the central 3dn ion and that of ligand ions were included). The calculated results from CMD and PTM were not only close to each other, but were also in agreement with the observed values. This suggested that the present defect models of the two Ti3+ centers in the LMA:Ti3+ crystal were suitable and that both CDM and perturbation theory methods were effective explanations of the spin-Hamiltonian parameters of 3d1 ions in crystals. The defect structures of both Ti3+ centers (which were quite different from the corresponding structures in the host LMA crystal, in particular, for center 1, the O octahedron changes from the trigonal elongation in the host LMA crystal to the trigonal compression in the Ti3+ center) were also estimated from the calculations.

Studies of the Defect Structures and g-Factors for Two Trigonal Ti3+ Centers in LaMgAl11O19:Ti3+ Crystal. W.C.Zheng, F.Wang: Journal of Applied Physics, 2007, 101[11], 113908