Resonant subwavelength control of the phase of spin waves reflected from a ferromagnetic film edge

Krzysztof Sobucki, Paweł Gruszecki, Maciej Krawczyk, Wojciech Śmigaj, Justyna Rychły

Published 2020-07-30Version 1

Using frequency-domain finite element calculations cross-checked with micromagnetic simulations, we demonstrate that the phase of spin waves reflected from an interface between a permalloy film and a bilayer can be controlled changing dimensions of the bilayer. Treating the bilayer formed by the permalloy film and a ferromagnetic stripe as a segment of a multi-mode waveguide, we show that spin-wave Fabry-Perot resonances of one of its modes are responsible for the high sensitivity of the phase of reflected waves to stripe width and the stripe-film separation. The bilayer can be treated as a magnonic counterpart of a metasurface since it enables manipulation of the phase of spin waves at subwavelength distances. Knowledge gained from these calculations might be used to design magnonic devices such as flat lenses for spin waves or detectors based on surface plasmon resonances phenomenon.