Wavelength-modulated spectra of some Fe³⁺ oxides

The wavelength-modulated reflectivity spectra in the visible and near uv of GdIG, LuFeO3, FeBO3, Fe2O3, Fe[NiFe]O4, and BaFe12O19 are reported. Features of both the exciton sideband and the charge-transfer spectra are observed. Comparison of these spectra allows some site assignments to be made. In particular the octahedrally coordinated Fe3+ ion is found to contribute a characteristic charge-transfer spectrum that occurs at lower energies than the tetrahedral Fe3+ charge-transfer spectrum. A further charge-transfer process between octahedral and tetrahedral Fe 3+ sites is suggested to explain the garnet spectra. © 1974 American Institute of Physics.