Excitation and Tuning of Spin Waves in Magnonic Crystals by Magnetic Coupling

Magnonic crystals with artificial micro/nanomagnetic pattern act as low-loss information carriers in many microwave devices. The excitation and control of spin waves inside is essential and fundamental in magnonic crystal applications. Herein, permalloy micro-disk patterns are constructed on a continuous permalloy film, and they succeed in exciting spin waves in this bilayer-structured magnonic crystal. The spin-wave modes can be effectively tuned by varying the periodic parameter (P) of upper-layer disk pattern, which is confirmed by the transition from single-peak to multi-peak in ferromagnetic resonance (FMR) spectra with P decreased from 4 to 0.5 mu m. The split in FMR spectra is reconstructed by micromagnetic simulation, revealing that three spin-wave modes are respectively excited by the domain walls of below-layer continuous film, geometrical restriction of permalloy micro-disk, and magnetic coupling between neighboring permalloy micro-disks. The tunable spin-wave behavior in this bilayer-structured magnonic crystal presents broad application prospect in programmable spintronic devices at micro/nanoscale. In the bilayer-structured magnonic crystal, the spin-wave modes can be effectively tuned by varying the periodic parameter of upper-layer disk pattern.image (c) 2024 WILEY-VCH GmbH