We have investigated the magneto-optical properties of Compositionally modulated Co/Pd superlattice thin films of various sublayer thickness and total thickness at a 632.8 nm wavelength. Films were deposited on glass and Si substrates by sputtering with Ar pressure from 2 mTorr to 30 mTorr. All samples retained the <111> texture and modulated structure as revealed by x ray diffraction. Magneto-Optical properties of the samples were measured with kerr loop tracer fabricated in our laboratory. Kerr hysteresis loop of films with Co sublayer thickness thinner than 4Å showed squre loops when Pd sublayer thickness was 9Å. All samples with 2Å thick Co sublayer showed square kerr hysteresis loops. Samples with rougher surface and columnar structure were fabricated with high Ar pressure, as revealed by surface and crosssection SEM photography of the film. We believe that higher coercivity at high sputtering presure is due to the morphology of the thin film.
Refractive index of optically thick Co-2 Å/Pd-9 Å film were determined with ellipsometer. We measured angular dependence of △ and Ψ and determined the refractive index by fitting the data with theoretical equation containing the index as a parameter. Using this index. We calculated the dependance of kerr angle on the total thickness of the film. From this fitting, we concluded that kerr rotation enhancement at thin sample ($\approx$100Å) was due to optical interference effect.
The SNR of the multi-layer structure Containing dielectric layers of various refractive index was calculated with computer. In the case of bilayer structure, the higer was refractive index, the hgher is the SNR. In the case of trilayer structure, the lower was the refractive index, the higher was the SNR.
