Spin dynamics in a Curie-switch

Ferromagnetic resonance properties of F-1/f/F-2/AF multilayers, where weakly ferromagnetic spacer f is sandwiched between strongly ferromagnetic layers F-1 and F-2, with F-1 being magnetically soft and F-2-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 F-1 and F-2 layers. Our theoretical calculations as well as measurements show that the key magnetic parameters of the spacer, which govern the ferromagnetic resonance in F-1/f/F-2/AF, are the magnetic exchange length (Lambda), effective saturation magnetization at T = 0 (m(0)) and effective Curie temperature (T-C(eff)). The values of these key parameters are deduced from the experimental data for multilayers with f = NixCu100-x, for the key ranges in the Ni-concentration (x = 54 divided by 70 at. %) and spacer thickness (d = 3 divided by 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.