First-Principles Investigation of Magneto-Optical Kerr Effect of Metallic Mutilayers

Magneto-optical Kerr effect (MOKE) of magnetic metallic multilayers, Fe/Pt, Co/Pt, Fe/Au and Co/Au, is investigated based on first-principles electronic structure calculations by using the FLAPW method. The MOKE spectrum of these systems can be classified into two photon-energy ranges, below and above 7 eV, along the final-state character in the optical transition. We have found that the spin-orbit splitting at the noble-metal site dominates the shape of the MOKE spectrum. This is because the spin-orbit splitting of the bands which are involved in the magneto-optical transition is mainly determined at the noble-metal site. Hence, the most important contribution to the dipole-transition matrix elements comes from the noble-metal site. Especially, d to p transitions with the majority spin at the noble-metal site are crucial for the MOKE spectrum below 7 eV. The large spin-orbit interaction at the noble-metal site induces the orbital splitting also at the 3 d transition-metal site through the band hybridizat...