Magneto-optical Spectra in Pd/Co Multilayers and Related Alloys

The magnetooptical Kerr spectra of Pd/Co multilayers and alloys prepared by DC magnetron sputtering system using an ultra-high vacuum chamber were measured between 1.24 and 5.90 eV. Analysis of the permeability tensor showed that the effect of plasma enhancement of the Kerr effect in Pd/Co multilayers was not so large as that in Pt/Co multilayers. The Kerr rotation spectra of multilayers had a different feature around 3 eV from that of corresponding alloys. We performed a simulation of Kerr rotation spectra by a virtual optical constant method assuming the presence of an interfacial PdCo alloy. It was found that the Kerr rotation spectra could not be explained by this assumption, suggesting that magnetically polarized Pd should be taken into account. We then performed a simulation assuming the presence of "magnetic Pd." As a result, we found that the peaks around 2.7 eV and 4.7 eV resulted from the "magnetic Pd" layers and the PdCo/Co layers, respectively.