First-Principle Studies on Magneto-Optical Anisotropy of Fe_x/Cu_x Superlattice

The interaction between the magnetization vector and the optical properties is described by the off-diagonal components of the dielectric tensor, which depends on the magnetization orientation. Here, we present our study of magneto-optical anisotropy (MOA) in Fe_x/Cu_x superlattice, where x is the number of atomic-layers, based on first-principle study. Calculations were carried out by using a full-potential linearized augmented plane wave (FLAPW) method with the generalized gradient approximation.[1] The optical conductivities tensor (or dielectric tensor) were estimated by the Kubo formula. The anisotropy of the absorptive parts of the off-diagonal optical conductivity tensor is determined in the photon energy range 0-8 eV. As a result, we observed that MOA was highest in Fe₂Cu₂ due to the orbital character of the partial density of d state significantly different by the change in the magnetization direction. The band-by-band decomposition of the MOA in Fe₁Cu₁, where the interband transitions are responsible for the MOA spectra around 1 eV, 2 eV, 3.5 eV, and 6 eV, is discussed. On the other hand, at 1.96 eV, magneto-optical constant Q increases in proportion to the value of x in transversal Kerr geometry.
Keywords: magneto-optical anisotropy, first-principles study, superlattice