Magnetostatic modes of a lateral ferromagnetic/ferromagnetic superlattice

In this Letter, we calculate the magnetostatic modes of a semi-infinite lateral ferromagnetic/ferromagnetic superlattice with the effective-medium theory and present the general features of the modes. The numerical calculations for Co/Ni superlattice show some interesting properties which different from the lateral ferromagnetic/nonmagnetic superlattice. Two branches of the surface modes appear for the superlattice. Comparing with the surface magnetostatic modes of bulk Ni, one branch of the mode is of high frequency; the other branch of mode is of low frequency.