Ferromagnetic resonance in a multilayer structure with indirect exchange coupling

The resonance dynamics of the magnetic moments of a multilayer exchange-coupled structure is studied in in-plane bias and microwave fields. The existence of a magnetocrystalline anisotropy is found to cause a minimum in the field dependence of the resonance frequency of the acoustic mode and the corresponding maximum in the magnetic susceptibility. A new mode with strongly different precession amplitudes of the magnetic moments of structure subsystems is found. This mode is shown to occur at the bias fields and the frequencies that are close to the values corresponding to the intersection of the acoustic and optical resonance branches, and this mode can effectively be controlled by varying the in-plane angle of the microwave field.