Abstract
Faraday rotation (FR) in a Ru4+-substituted magnetic garnet was measured in the visible to near ultraviolet wavelength region. An FR contribution due to Ru4+ ions was observed at around 2.8 eV and increased with increasing temperature. On the basis of the energies of charge transfer (CT) transitions in a (Ru4+O2-6)8- cluster calculated by an unrestricted SCF-SW-Xα method and the analysis of magnetic circular dichroism spectra measured in a Ru4+-substituted gadolinium gallium garnet, the transition at around 2.8 eV is assigned to the allowed CT transition of the lowest energy from O2- 2p to Ru4+ 4d orbitals, that is, the t1u (π) → t2g* transition. Furthermore, the temperature dependences of FR spectra are explained by a thermally induced FR from the first excited state of Ru4+.
