Collective spin waves in RKKY interlayer-coupled Ni 80 Fe 20 /Ru/Ni 80 Fe 20 nanowire arrays.

We report on a comprehensive investigation of collective spin waves in Ruderman-Kittel-Kasuya-Yosida (RKKY) interlayer-coupled Ni 80 Fe 20 (10 nm)/Ru(1.0 nm)/ Ni 80 Fe 20 (10 nm) nanowire (NW) arrays. We employed Brillouin light scattering to probe the field- and wavevector-dependences of the spin-wave frequency spectra. The acquired data were subsequently analyzed and interpreted within the framework of a microscopic Hamiltonian-based method, enabling a detailed understanding of the observed spin-wave behavior. We observed the propagation of Bloch-type collective spin waves within the arrays, characterized by distinct magnonic bandwidths that stem from the combined influence of RKKY interlayer and inter-NW dynamical dipolar interactions.