Enhanced magneto-optical Kerr effect in oxidized Co thin films

Abstract

We have studied the structural and magneto-optical properties of postdeposition oxidized Co thin films. The oxidization process leads to the formation of a double-layered structure of fcc Co 3 O 4 on top of metallic Co. The magneto-optical Kerr effect ͑MOKE͒, measured in the range 0.8 eV рE Ph р5.5 eV reveals characteristic dependencies of the MOKE spectra on annealing temperature and time. In particular, we observe resonance-type enhancements of the Kerr effects by up to a factor of 10 compared with unannealed metallic Co. The experimental data are quantitatively reproduced by bilayer optical stack calculations.