Magneto-optical and optical properties of GdFe films

A thin SiN layer was coated upon GdFe/Si film in order to avoid the surface contamination and oxidation. From the SiN/GdFe interface, the genuine optical constants of GdFe layer were obtained using spectroscopic ellipsometry. The magneto-optical Kerr effect in the large energy range between 1.6 eV and 4.5 eV was also studied. Calculations show that the MOKE peak in the high energy range originates not only from its intrinsic magneto-optical charateristics of GdFe layer, but also from the interference of SiN layer. When the Fe content decreases from 79.3 to 75.8 at %, the sign change of the complex Kerr rotation was observed and found being induced by the spin-flip.