The polar magneto-optical Kerr effect and the dielectric tensor elements of CoFe2−<i>x</i>Al<i>x</i>O4 0.1≤<i>x</i>≤1 in the photon energy range 0.65≤<i>h</i>ν≤4.5 eV

Abstract

The polar magneto-optical Kerr rotation and ellipticity have been determined for ceramic CoFe2−xA1xO4 samples (0.1≤x≤1.0) in the photon energy range 0.65≤hν≤4.5 eV. In the same energy range spectroscopic ellipsometry has been used to determine the optical properties. The results have been combined in the calculation of the complete dielectric tensor. Two diamagnetic crystal field transitions of Co2+ (Td) at 0.8 and 2.0 eV have been identified as well as a broad paramagnetic transition also at ∼2.0 eV. This last transition is assigned to a Co2+→Fe3+ charge transfer transition on octahedral lattice sites.