Inelastic spin-wave beam scattering by edge-localized spin waves in ferromagnetic thin film

Abstract

Spin waves (SWs) have promise as chargeless information carriers in energetically efficient beyond-CMOS systems. Among their many advantages are easy of obtaining nonlinearities and a variety of possible interactions of SWs with other types of excitations. While rapid advances in magnonic research have already yielded impressive results, the development of inter-modal nonlinear effects for propagating modes remains an open problem, as does scalability. In this paper, we study theoretically the dynamic interaction of SWs localized at the edge of a thin ferromagnetic film, with the SW beam incident at this edge. Among the reflected waves, we find inelastically scattered SW beams at frequencies increased and decreased by the frequency of the edge SW relative to the specular beam. This phenomenon of three-magnon interaction is a purely magnonic counterpart of Brillouin light scattering by SWs. We show that in this scattering process, the dynamic magnetostatic interactions are decisive, indicating the ubiquity of the process. Moreover, we observe an angular shift between the primary incident and the frequency-dependent reflected SW beams, which leads us to propose magnonic demultiplexing of the signal coded in the edge SWs.