[en] Ferromagnetic resonance properties of F₁/f/F₂/AF multilayers, where weakly ferromagnetic spacer f is sandwiched between strongly ferromagnetic layers F₁ and F₂, with F₁ being magnetically soft and F₂—magnetically hard due to exchange pinning to antiferromagnetic layer AF, are investigated. Spacer-mediated exchange coupling is shown to strongly affect the resonance fields of both F₁ and F₂ layers. Our theoretical calculations as well as measurements show that the key magnetic parameters of the spacer, which govern the ferromagnetic resonance in F₁/f/F₂/AF, are the magnetic exchange length ($\mathrm{\Lambda <!--\; ??\; -->}$), effective saturation magnetization at T  =  0 (m ₀) and effective Curie temperature ($T_{\text{C}}^{\text{eff}}$). The values of these key parameters are deduced from the experimental data for multilayers with f  =  Ni_xCu_100−x, for the key ranges in the Ni–concentration ($x=54÷<!--\; ??\; -->70$ at. %) and spacer thickness ($d=3÷<!--\; ??\; -->6$ nm). The results obtained provide a deeper insight into thermally-controlled spin precession and switching in magnetic nanostructures, with potential applications in spin-based oscillators and memory devices. (paper)