Tuning of the spin wave band structure in nanostructured iron/permalloy nanowire arrays

This chapter presents the results of a combined experimental and theoretical investigation of the spin wave band structure in bilayered iron/ permalloy (Fe/Py) nanowires (NWs) with either "rectangular" cross section (bottom and upper layers of equal width) or "L-shaped" cross section (upper layer of half width). A similar dispersive mode is also present in L-shaped NWs, but the mode amplitude is concentrated in the Py NW portion not covered by Fe. The chapter analyzes the dispersion of collective spin waves in arrays of iron/permalloy nanowires with either rectangular or L-shaped cross section by using Brillouin light scattering and numerical simulations. The measurements relative to the frequency dispersion of the spin waves were satisfactorily reproduced by micromagnetic simulations, which also allow to calculate the spatial profiles of the modes in the few layers.