MAGNONS, MAGNETIC POLARITONS, AND MAGNETO STATIC WAVES

Electrodynamical properties of magnetically ordered media are analysed theoretically. Two types of magnetic materials, namely ferromagnets a nd antiferromagnets, are considered and the effect of the magnetic sub system on the properties of the host metal are discussed. Various type s of elementary excitations, such as magnetic polaritons, magnetostati c waves, and magnons, are examined within the conventional quasipartic le framework. The dispersion of the quasiparticles as a function of th e relation between the characteristic frequencies of electrical and ma gnetic nature is described over a wide range of frequencies. Particula r attention is given to the statistical thermodynamics and kinetics of the magnetic materials. The possibility of Bose - Einstein condensati on in a magnon gas is analysed and the kinetic theory of electron-assi sted magnetostatic wave damping in a ferromagnetic metal is developed. The dispersion of surface polaritons is examined in detail. Example s olutions of spatially non-uniform problems with spatial dispersion are discussed which show this latter to be of particular importance in fe rromagnetic materials.