Ferromagnetic resonance study in exchange coupled magnetic/'non-magnetic' multilayer structures

n exchange coupled resonance theory for the magnetic/"non-magnetic" tri-layer and multilayer systems was developed from that of a single ferromagnetic film. The uniform mode in the single ferromagnetic layer system is split into a family of coupled layer modes within which the precession amplitude is nearly uniform in each magnetic layer but varies rather significantly from one magnetic layer to the other. The dispersion relation for these modes depends sensitively on the exchange coupling strength, ;Ferromagnetic resonance (FMR) measurements were performed on several series of Co/Ru, Co/Pt and Fe/Pt trilayer and multilayer films to study the variation of ;In the Co/Ru/Co trilayer structures, both the sign and amplitude of ;In the Co/Pt and Fe/Pt multilayer films, only parallel coupling was observed.