Two-Dimensional Twisted Ferromagnetic Domain Wall as a Spin-Wave Diffraction Grating

Abstract

We present a theoretical study of spin-wave scattering by a twisted domain wall (DW) in a two-dimensional ferromagnet with easy-axis anisotropy. While the twisted DW generates an effective gauge field for spin waves, leading to a deflection of their trajectories, our main focus is on a distinct effect that arises when a hard-axis anisotropy is present in addition to the easy-axis anisotropy. In this case, the translational symmetry of the spin-wave Hamiltonian along the DW is broken, resulting in a periodic modulation of the Hamiltonian. This periodicity leads to the formation of multiple diffracted spin wave modes on both sides of the DW, engendering a DW-induced magnonic diffraction pattern. The interplay between the emergent gauge field and the anisotropy-induced periodicity reveals rich spin-wave dynamics and suggests potential applications for manipulating magnon flow in two-dimensional magnetic textures.