材料期刊网

The EPR zero-field splittings of Fe3+ doped in MgTiO3 and LiTaO3 are studied by diagonalizing the complete energy matrices of the electron-electron repulsion, ligand-field and spin-orbit coupling interactions for a d(5) configuration ion in a trigonal ligand-field. It is shown that, when Fe3+ is doped in a MgTiO3 or LiTaO3 crystal, the local lattice structure around the octahedral Fe3+ center has an obvious distortion along the C-3 axis. By simulating the second- and fourth-order EPR parameters D and (a - F) simultaneously, the local structure parameters of Fe3+ doped in MgTiO3 and LiTaO3 crystals are determined, which reveal that Fe3+ occupies both the Mg2+ and T& sites in the MgTiO3:Fe3+ system and Occupies the Li+ site rather than the Ta5+ site in the LiTao(3):Fe3+ system. The results accord with the ENDOR and EPR experiments. - PACS numbers: 71.70.Gm; 75.30.Et; 71.70.Ch.