Magnonic

Magnonic is an adjective related to magnons, the quantized spin-wave excitations in magnetic materials, and to magnonics, the field that studies using spin waves for information processing and signal transmission. In magnetic systems, spin waves arise from coherent precession of spins, and when treated as particles, these excitations are magnons.

Magnonics investigates the dispersion relations, modes, and damping of spin waves, as well as their coherent manipulation and control. Magnons can carry information at microwave to sub-terahertz frequencies and, in principle, with low energy dissipation compared with charge-based carriers. The field encompasses both exchange-dominated short-wavelength and dipolar-dominated long-wavelength spin waves, along with engineered structures that tailor their propagation.

Applications include magnonic crystals and metamaterials that create band structures for spin waves, magnonic waveguides and circuits for information processing, and reconfigurable magnonic devices. Logic concepts based on interference, phase control, and nonlinear interactions of spin waves aim to realize low-power computing and microwave signal processing, including filters, multiplexers, and nonreciprocal devices.

Materials commonly used in magnonics are low-damping magnetic insulators such as yttrium iron garnet (YIG), as well as metallic ferromagnets like permalloy and cobalt ferrites. Nanomagnonics explores nanoscale confinement and integration with other platforms. Characterization methods include Brillouin light scattering, ferromagnetic resonance, and spin-wave spectroscopy.

Challenges include damping, thermal noise, and integration with semiconductor technologies, as well as scalable fabrication and efficient transduction between magnons and other information carriers. Ongoing research explores quantum magnonics, where magnons couple to superconducting qubits or optical fields, linking magnonics to quantum information science and spintronics.