Spin dynamics of polycrystalline Ni films on Si substrate

We have prepared thin Ni films by direct electrodeposition onto Si substrates and investigated the magnetization dynamics up to 9 GHz. Films with typical thickness of 200 nm show good adhesion to the substrate. Experimental absorption spectra were fitted using a model, which combines the magnetization dynamics according to Landau-Lifshitz-Gilbert and eddy current contribution. Damping parameters ranging from 0.12 to 0.08 were obtained. These values are larger than the intrinsic damping parameter of 0.064 for Ni, which indicates that the effect of eddy current is the prime contribution to line broadening in the electrodeposited Ni/Si structure. The dependence of damping parameter on applied field also supports this idea, the larger the applied field the smaller the damping parameter is.