Ferromagnetic resonance (FMR) in ferromagnet/normal metal bilayer system

We have performed ferromagnetic resonance measurements in ferromagnet/normal metal bilayers. Our sample was made by depositing thin film of gold on top of permalloy. With a GHz ac magnetic field applied parallel to the sample, we measured the transmission while sweeping the dc field. In addition to the ferromagnetic resonance coming from the permalloy film, we observed additional structure which we associate with a finite magnetization in the normal metal film.