Natural oxide formation on cobalt investigated with the magneto-optical kerr effect

We have studied the magneto-optical Kerr effect (MOKE) of air-annealed Co thin films. Structural investigations reveal the formation of a double layered Co oxide (fee Co3O4) / Co metal structure. MOKE spectra, measured in the photon energy range 0.8 ≤ Epn ≤ 5.5 eV, show charactistic changes as function of the annealing time and temperature. In particular, we observe the occurrance of resonance type enhancements with peak Kerr rotations of θK = -5.5 deg. The experimental spectra can be quantitatively reproduced using bilayer optical stack calculations. © 1997 IEEE.