OPTICAL AND MAGNETOOPTICAL POLAR KERR SPECTRA OF FE3O4 AND MG2-SUBSTITUTED OR AL3+-SUBSTITUTED FE3O4()

The diagonal elements of the dielectric tensor, between 0.5 and 5.0 eV , and the magneto-optical polar Kerr spectra, between 0.7 and 4.0 eV, have been determined for a synthetic crystal of magnetite, Fe3O4 and a systematic investigation of these properties for Mg2+ and Al3+ substi tutions has been carried out. From these spectra the off-diagonal elem ents of the dielectric tensor was calculated between 0.7 and 4.0 eV. T hrough fitting simultaneously both the diagonal and the off-diagonal e lements of this tensor with one set of parameters and consistently for all partially substituted ferrite samples. we were able to resolve th e magneto-optital spectrum of Fe3O4 between 0.7 and 4.0 eV. The observ ed trends in the major transitions upon substitution provide the exper imental evidence for intervalence charge transfer and intersublattice charge transfer transitions in Fe3O4.