The magneto-optical Kerr effect (MOKE) has been investigated for ferrimagnetic spinel compounds MCr2S4 (M=Mn and Fe). In FeCr2S4, the gigantic magneto-optical response, reaching up to 4.3° in Kerr rotation, is observed at the energy of the intra-atomic d-d transition of Fe2+, E5→T25. By analyzing the resonance feature in the framework of the ligand field theory, we have clarified that the large oscillator strength enhanced by the strong covalency of the ligand sulfur as well as the local breakdown of inversion symmetry at the Fe2+ site is responsible for the gigantic signal. In MnCr2S4, the spin-forbidden d-d transition (A16→T14) of Mn2+ is revealed in the MOKE spectra, which is not discernible in the optical reflectivity spectra.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2005 Oct 15|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics