MAGNETIC-RESONANCE IN COUPLED DOUBLE FILMS SEPARATED BY NONMAGNETIC INTERLAYER

Spin wave resonance (SWR) at 16 GHz in the perpendicular configuration is studied in double NiFe films separated by Cu interlayer. The influ ence of Cu thickness d in the range of 0.5-2.7 nm on the mode splittin g is discussed. A theoretical model is proposed, that includes both th e 'bulk' coupling between the magnetizations M1 and M2 with the energy density E = -KM.M2 and the interface coupling described by E = A12(m1 -m2)2, where m and m2 are the microwave magnetizations. It is shown th at the model with two coupling constants K = K0 e(-d/q) and A12 = A0 e (-d/t), where q = 2.5 nm, t = 0.25 nm, K0 = 132 erg/cm2, A0 = 10 erg/c m2 agrees quite well with the experimental data. The existence of two different damping constants q and t indicates that at least two mechan isms are responsible for the interaction between magnetic layers: long range interactions acting across the nonmagnetic interlayer, e.g. str ess-induced anisotropy and direct short range exchange.