Magneto-optical effects have been investigated over the infrared visible spectral range in ACr2O4 (A=Fe,Co) spinel oxides with noncollinear spin orders in their ground states. We found large magneto-optical Kerr rotation and ellipticity at the on-site d-d transitions of the A2+ ions located within the charge gap. The magneto-optical Kerr rotation of Kerr≈12 observed in CoCr2O4 is unprecedentedly large among magnetic semiconductors and points toward the uniqueness of tetrahedrally coordinated Co2+ ions in generating strong magneto-optical response. Criteria of strong magneto-optical effects emerging at on-site d-d transitions of transition metal ions are discussed.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics