Spin-wave resonance in $\mathrm{NiFe/Dy}_x\mathrm{Co}_{1-x}/\mathrm{NiFe}$ structures with positive exchange interaction value between the ferromagnetic layers

Standing exchange spin-waves spectrum of $\mathrm{Ni_{80}Fe_{20}/Dy_{20}Co_{80}/Ni_{80}Fe}_{20}$ magnetic sandwiches was investigated by the spin-wave rasonance technique. The layer of the amorphouse ferrimagnetic alloy has precompensation composition, therethore its magnetic structure provided positive value of the exchange coupling between the ferromagnetic layers. It was shown that spin modes of SWR specrum whitch according to the Kittel's ratio $H_r(n)\sim n^2$ are the standing acoustic exchange spin oscillations. It was determined, that spin modes of optical satellites of the SWR acoustic peaks are characterized by another ratio $H_r(n)\sim n^{5/2}$.