Control of spin-wave transmission by a programmable domain wall

TLDR

Spin-wave manipulation is key to magnonic devices, and programmable domain walls in CoFeB films offer a route to control spin-wave transport for logic and memory applications. The study demonstrates programmable spin-wave filtering by reconfiguring pinned 90° Néel domain walls and proposes a two-domain-wall spin-wave valve. This is achieved by abruptly rotating the uniaxial magnetic anisotropy in a continuous CoFeB film to reset the domain-wall spin structure. Broad head-to-head or tail-to-tail walls are largely transparent, whereas head-to-tail walls are narrow and strongly reflecting, allowing the valve to switch spin-wave transmission from nearly 100 % to 0 %.

Abstract

Active manipulation of spin waves is essential for the development of magnon-based technologies. Here, we demonstrate programmable spin-wave filtering by resetting the spin structure of pinned 90° Néel domain walls in a continuous CoFeB film with abrupt rotations of uniaxial magnetic anisotropy. Using micro-focused Brillouin light scattering and micromagnetic simulations, we show that broad 90° head-to-head or tail-to-tail magnetic domain walls are transparent to spin waves over a broad frequency range. In contrast, magnetic switching to a 90° head-to-tail configuration produces much narrower and strongly reflecting domain walls at the same pinning locations. Based on these results, we propose a magnetic spin-wave valve with two parallel domain walls. Switching the spin-wave valve from an open to a closed state changes the transmission of spin waves from nearly 100 to 0%. Active control over spin-wave transport through programmable domain walls could be utilized in magnonic logic devices or non-volatile memory elements.