Electron paramagnetic resonance parameters of Mn4+ ion in h-BaTiO3 crystal from a two-mechanism model

The EPR parameters (g factors g ‖, g ⊥ and zero-field splitting D) of Mn4+ ion in h-BaTiO3 crystal are calculated from the complete high-order perturbation formulas based on a two-mechanism model for the EPR parameters of 3d 3 ions in trigonal symmetry. In the model, not only the widely used crystal-field mechanism, but also the charge-transfer mechanism (which is not considered in crystal-field theory) are included. The calculated results are in reasonable agreement with the experimental values. The relative importance of charge-transfer mechanism to EPR parameters and the defect structure of Mn4+ centre in h-BaTiO3 crystal obtained from the calculations are discussed.