Magnetic Charge Fingerprints in the Spin-Wave Spectrum of Three-Dimensional Artificial Spin Ice.

Three-dimensional artificial spin ice (3D-ASI) is a programmable nanoscale magnetic network showing emergent magnetic charge states with potential for reconfigurable dynamics. Here, we show that magnetic charge states in a 3D-ASI leave experimentally measurable charge-sensitive spectral signatures in the spin-wave spectrum, enabling charge-state readout via magnonics. Using Brillouin light scattering spectroscopy supported by micromagnetic simulations, we demonstrate that charged and charge-neutral vertices produce qualitatively distinct spin-wave spectra in a purely three-dimensional lattice. Spatially resolved mode analysis reveals that magnetic charges selectively control spin-wave localization and quantization, establishing a direct link between vertex microstate and dynamic response. We further demonstrate that configurational anisotropy inherent to the 3D architecture allows spin-wave reconfiguration by varying the orientation of an applied field. These results position spin-wave spectroscopy as a dynamic, noninvasive probe of magnetic charge states and open pathways to reprogrammable, low-power 3D magnonic and neuromorphic devices.