Spin-wave interference in magnetic vortex stacks

Spin waves with wavelengths in the nanometre range could serve as data carriers in future magnonic logic or signal processing devices. We investigate the interference of spin waves emitted from magnetic vortices in two exchange-coupled vortex stacks. The spin-wave dynamics are studied using scanning transmission X-ray microscopy and micromagnetic simulations. Stacks of vortices provide an excellent controllability of spin-wave properties including a tunable wavelength in the 100 nm regime and manipulation of their propagation direction via the magnetisation configuration. Furthermore, interference gives rise to amplified or reduced spin-wave amplitudes in distinct areas of the structure providing controlled confinement crucial for future applications of spin waves. Spin waves are promising candidates as a building block for future magnonic devices. The authors present a combined numerical and experimental study of spin-wave interferences in stacks of magnetic vortices that are efficient spin-wave emitters in the nanometre regime.