材料期刊网

The electron paramagnetic resonance (EPR) parameters (zero-field splitting D and g factors g(parallel to), g(perpendicular to)) of Cr4+ ions in Ca-2 GeO4 crystals have been calculated from the complete high-order perturbation formulas of EPR parameters for a 3d(2) ion in trigonal MX4 clusters. In these formulas, in addition to the contributions to EPR parameters from the widely used crystal-field (CF) mechanism, the contributions from the charge-transfer (CT) mechanism (which are often neglected) are included. From the calculations, it is found that for the high valence state 3d(n) ions in crystals, the reasonable explanation of EPR parameters (in particular, the g factors) should take both the CF and CT mechanisms into account.