Magnetostatic modes of lateral metal magnetic superlattices

We investigate magnetostatic modes of lateral magnetic superlattices compos ed of metallic magnetic layers and insulating nonmagnetic layers, with an e ffective-medium theory. We assume that the in-plane waves always propagate normal to the static magnetization for an arbitrary external field applied parallel to the surface, and that the damping results from eddy currents. S ome particular features of the frequency and damping are seen, for example, the damping is not the lowest for a higher applied field Vertical to the m agnetic-nonmagnetic layers, but it is the lowest fur a smaller applied fiel d. These features of the frequency and damping are not only governed by the conductivity and wave number, hut also by the direction and magnitude of e xternal magnetic field. The patterns of obtained calculation curves are com plicated. Our results in the limiting case of conductivity sigma=0 are cons istent with those in the previous works. The numerical calculations are pre sented for the Ni-vacuum superlattice.