Light scattering on spin waves of thin ferromagnetic films and heterogeneous double layers

Iron, nickel and permalloy films were evaporated onto saphire and silicon substrates, and saturation magnetization, exchange constant and the gyromagnetic ratio were determined from measurements of the dispersion of the spin wave energies as a function of film thickness, which varied between 5 and 100 nm. Coupling of the surface modes of two ferromagnetic layers, separated by a nonmagnetic spacer was examined. Asymmetry in the ratio of the intensities of Stokes and anti-Stokes scattering down to film thicknesses of some nanometers and an increase of the scattering intensity upon decreasing film thickness were studied. The latter appears for suitable combinations of film and substrate materials. The maximum of the intensity versus thickness curve peaks at 5 nm.