A magnon is the quasiparticle of a spin wave. The source dossier quotes a ScienceDirect topic definition: a spin wave is "a collective motion of magnetic moments in magnetically ordered materials, playing a crucial role in spintronics as a carrier of spin current, which is the flow of spin angular momentum."
Role in the magnon space–time crystal
Magnons are the constituent quasiparticles of the room-temperature Space-Time Crystal reported by the Max Planck Institute for Intelligent Systems and collaborators in Phys. Rev. Lett. 126, 057201 (2021). In that experiment, a strip of magnetic material (permalloy) was placed on a microscopic antenna through which a radio-frequency current was sent. The microwave field triggered an oscillating magnetic field that stimulated magnons in the strip. Magnetic waves migrated into the strip from left and right, spontaneously condensing into a recurring pattern in space and time.
The abstract reports that interactions of magnons with the STC appear as lattice scattering, generating ultrashort spin waves down to 100-nm wavelengths that cannot be described by classical dispersion relations for linear spin-wave excitation. The press release quotes Nick Träger: "We took the regularly recurring pattern of magnons in space and time, sent more magnons in, and they eventually scattered. Thus, we were able to show that the time crystal can interact with other quasiparticles."
Related work
- Space-Time Crystal — the magnon crystal.
- max-planck-institute-for-intelligent-systems — the lead institution.
Source notes & attribution
- https://rexresearch.com/WilczekTimeCrystals/WILCZEKTimeCrystals.html