Influence of the Vertex Region on Spin Dynamics in Artificial Kagome Spin Ice

We present experimental and theoretical studies of spin-wave mode dynamics in artificial kagome spin ice vertices made of three identical 15-nm thick elongated Ni80Fe20 nano-islands (macrospins). We consider several possible configurations, from completely disjointed macrospins (full dipolar inter-element interactions) to fully jointed macrospins (full dipolar-exchange interactions). Using angular-resolved magnetic field dependent broadband ferromagnetic resonance (FMR), we demonstrate the occurrence of a mode localized in the vertex region as indicated by the distinct behavior of the FMR spectra at different angles and configurations. Theoretical calculations using micromagnetic simulations support the existence, origin, and behavior of this mode by interpreting it as a localized, quasi-uniform Kittel mode. Furthermore, our findings pave the way for designing the most appropriate network consisting of ferromagnetic nanomagnets for specific application purposes in magnonics.