Reconfigurable spin-wave dynamics in two-dimensional quasiperiodic magnonic crystals

Abstract

Active control of spin-wave properties is at the heart of on-chip reconfigurable magnonics, which promise development of energy efficient and miniaturized on-chip processing and communication devices in the GHz and sub-THz frequency range. Here, we demonstrated active control of spin-wave spectra in two-dimensional nanoscale antidot lattices arranged in shifted honeycomb and octagonal symmetries by varying the antidot diameter using broadband ferromagnetic resonance. Both these lattices exhibited stark variation in the spin-wave spectra with antidot diameter, besides the variation of the strength and orientation of bias magnetic field. With increasing diameter number of spin-wave modes gradually increased, and the position of mode splitting shifted to higher magnetic field due to ensuing increase in the demagnetizing field governing the spin-wave extension or localization in the lattices. The bias-field angle variation revealed higher-order rotational symmetry characteristic of quasi-periodic structure. Micromagnetic simulations qualitatively reproduced the experimental observations, and simulated spin-wave mode profiles revealed extended and standing spin-wave modes and their mutual conversion with bias-field angle in both lattices. The contrasting variation in the amplitude of rotational symmetry of spin-wave frequency with antidot diameter was interpreted by the variation of spin-wave mode profiles as well as the simulated internal magnetic field variation. Such efficient tunability of spin-wave properties with internal structure and external control parameters and higher-order rotational anisotropy in these atypical magnonic crystals will promote them for applications in on-chip reconfigurable magnonic devices.