An investigation of the EPR zero-field splitting of Fe 3+ ions at tetragonal sites in Tl 2MgF 4 and Tl 2ZnF 4 crystals

Abstract

By analyzing the EPR zero-field splitting parameters of Fe 3+ located at tetrahedral site in Tl 2MgF 4 and Tl 2ZnF 4 crystals, the local lattice structure for Fe 3+ doped in Tl 2MgF 4 and Tl 2ZnF 4 crystals is theoretically studied by diagonalizing the complete energy matrices for a d 5 configuration ion in a tetragonal ligand-field. From the calculation, the local lattice structure parameters R ⊥ = 1.8914 Å, R ∥ = 1.84699 Å and R ⊥ = 1.88229 Å, R ∥ = 1.84490 Å for tetragonal Fe 3+ center in Tl 2MgF 4 and Tl 2ZnF 4 crystals are determined, respectively. This result suggests that the ligand-fluorines on the C 4 axis deviate easily in both two crystals, which is consistent with the conclusion drawn by earlier workers.