Scattering properties induced by an asymmetric nanowell on ferromagnetic ultrathin film Original Research Article

In this paper, we develop an analytical and numerical formalism to study the coherent scattering and magnons transport properties via an atomic nanowell configuration. In particular, we study an asymmetric nanowell occurring in ultrathin film composed of five ordered ferromagnetic layers. The coherent transmission and reflection scattering cross sections via the nanowell domain, for spin waves incident from the bulk waveguide, are determined with the use of the matching method. Only the nearest neighbors exchange interactions are considered between the spins in the studied model. The effects of varying the local magnetic exchange interaction on the nanowell zone are analyzed for three different cases, to investigate the influence of softening and hardening of the magnetic boundary conditions. The results illustrate the occurrence of Fano resonances in the transmitted and the conductance spectra due to the coherent coupling between traveling magnons and the localized spin states in the neighborhood of the nanowell domain. The numerical results yield an understanding of the relationship between the coherent magnon transmission and the geometric configuration of the magnetic nanowell.