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Description
Magnonic crystals (MCs) with nanoscale periodic modulation enable control of spin-wave (SW) band structures for radio-frequency (RF) signal processing. While one-dimensional (1D) MCs provide frequency-selective transmission via Bragg scattering, extending periodicity to two dimensions (2D) enables more flexible band-structure engineering and controlled SW routing.
Here, we realise nanoscale 1D MCs based on 100 nm-thick yttrium iron garnet (YIG) nanowaveguides patterned with periodic nanoholes. Spin-wave propagation over distances exceeding 5 µm is demonstrated using propagating spin-wave spectroscopy (PSWS) and micro-focused Brillouin light scattering (μ-BLS) in the Damon–Eshbach geometry. Transmission and rejection bands appear in the 7.5–10.5 GHz range, with up to six band gaps and signal suppression reaching 26 dB, confirming strong Bragg reflection. Nanoscale confinement yields sharp band edges and reduced multimode contributions. Micromagnetic simulations reproduce the band structure and reveal two anticrossings at 3.1 and 18.7 rad/µm, with single-mode operation below the first anticrossing.
Extending to 2D MCs lithographically realised as planar antidot lattices from 100 nm-thick YIG films, we investigate SW propagation using PSWS and μ-BLS in the in-plane geometries. Defect-free and engineered-defect configurations enable increased functional density and controlled SW routing through defined defect channels, providing a basis for advanced magnonic systems, including topological MCs [6] and three-dimensional magnonic nanocrystals.
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