Tunable spin wave properties in [Co/Ni80Fe20]r multilayers with the number of bilayer repetition

Tunability of spin waves in [Co/Ni80Fe20](r) multilayer films by varying the number of bilayer repetition ( r) is investigated using Brillouin light scattering (BLS) spectroscopy. Conventional magnetometry shows a monotonic increase in the in-plane anisotropy with r. BLS spectra show a number of distinct modes, which were found to be Damon-Eshbach and perpendicular standing spin wave modes confined in several bilayers with different mode numbers by macrospin modelling. The extracted values of the magnetic parameters from the spin wave measurements agree reasonably well with the magnetometry results. A qualitative analysis of the dependence of BLS intensity of PSSW modes on the corresponding thickness has also been performed using a light-scattering theory for confined geometries. The results of the calculations are in agreement with experimental data.