Nanomagnonics

Nanomagnonics is a field within nanomagnetism and magnonics that studies the generation, propagation, manipulation, and detection of spin waves (magnons) in nanoscale magnetic structures. It seeks to use magnonic excitations as information carriers for computation and signal processing, with a focus on nanoscale confinement, integrated devices, and low-power operation.

Spin waves are collective excitations of spins in ordered magnetic materials. In nanoscale systems, spin waves form discrete modes determined by geometry, thickness, material parameters, and boundary conditions. Magnons can be excited by microwave fields, spin-transfer torques, spin-orbit torques, or optical pumping and detected by Brillouin light scattering, magnetoresistive sensors, or time-resolved magneto-optics. In nanostructures, damping, nonlinearity, and interactions with phonons and electrons shape propagation and coherence.

Materials and platforms: ultralow-damping ferrimagnetic insulators such as yttrium iron garnet (YIG) thin films, permalloy, CoFeB, Heusler alloys, and magnetic tunnel junctions. Nanostructures include nanowires, nanodots, magnonic crystals, and waveguides. Techniques include micromagnetic simulations (MM), time-resolved spectroscopy, Brillouin light scattering, and electrical methods via spin-torque or spin-Hall effect to excite and read magnons.

Applications: magnonic logic elements, reconfigurable field-programmable magnonic networks, phase and frequency filtering, delay lines, and microwave signal processing. Nanomagnonics promises reduced energy per operation and novel computing paradigms such as wave-based or neuromorphic architectures.

Challenges: maintaining low damping, efficient nanoscale excitation and detection, integration with CMOS electronics, interconnects, thermal stability, and fabrication imperfections that limit coherence. Research aims to harness topological magnons, nonlinear effects, and hybrid systems coupling magnons with photons, phonons, or superconducting qubits to enable scalable nanoscale magnonic networks.