材料期刊网

The EPR parameters (D, g parallel-to and g perpendicular-to) for chromium doped MgAl2O4 and ZnAl2O4 spinels have been calculated from the crystal-field theory relative to the structural parameters of these crystals by using the parameters obtained from the optical spectra. The results show reasonable agreement with the experimental findings, suggesting that the calculated method is suitable. Based on this method, we estimate approximately the anion distribution parameter u of ZnGa2O4 spinel from the EPR and optical spectra of ZnGa2O4:Cr3+ crystal. Considering that there may be more or less some relaxations of ligands due to the substitution of impurity Cr3+ for Ga3+ ions in ZnGa2O4 crystal, which are difficult to know, the reliability of the estimated parameter u(almost-equal-to 0.381 +/- 0.001) should be checked by other methods.