Amplifying spin waves along Néel domain wall by spin–orbit torque

Traveling spin waves in magnonic waveguides undergo severe attenuation, which tends to result a finite propagation length of waves, even magnetic materials with the accessible lowest damping constant, heavily restricting development devices. Compared traditional waveguides, propagating along strip domain wall are expected exhibit enhanced transmission. Here, we demonstrate theoretically and through micromagnetic simulations that spin–orbit torque associated ferromagnet/heavy metal bilayer can efficiently control attenuation Néel-type despite complexity ground-state magnetization configuration. The direction electric current applied heavy-metal layer determines whether these amplified or further attenuated otherwise. Remarkably, our reveal effective densities required tune decay such just ∼1010 A m−2, roughly an order smaller than those conventional waveguides. Our results will enrich toolset for technologies.