Spectroscopic ellipsometry and magneto-optical Kerr effect spectroscopy study of thermally treated Co₆₀Fe₂₀B₂₀ thin...

We report the optical and magneto-optical properties of amorphous and crystalline Co₆₀Fe₂₀B₂₀ films with thicknesses in the range of 10 nm to 20 nm characterized using spectroscopy ellipsometry (SE) and magneto-optical Kerr effect (MOKE) spectroscopy. We derived the spectral dependence of the dielectric tensor from experimental data for samples prior and after annealing in vacuum. The features of the dielectric function can be directly related to the transitions between electronic states and the observed changes upon annealing can be ascribed to an increase of the crystalline ordering of CoFeB.