What is "spin wave"

n. (context physics English) a wave, propagated through a crystal lattice as a result of changes in the spin angular momentum of electrons in the lattice

Spin waves are propagating disturbances in the ordering of magnetic materials. These low-lying collective excitations occur in magnetic lattices with continuous symmetry. From the equivalent quasiparticle point of view, spin waves are known as magnons, which are boson modes of the spin lattice that correspond roughly to the phonon excitations of the nuclear lattice. As temperature is increased, the thermal excitation of spin waves reduces a ferromagnet's spontaneous magnetization. The energies of spin waves are typically only in keeping with typical Curie points at room temperature and below. The discussion of spin waves in antiferromagnets is beyond the scope of this article.