Dynamic topological solitons in a two-dimensional ferromagnet

It is shown that stable, skyrmion-type, dynamic solitons can be constructed for a wide class of two-dimensional models of anisotropic ferromagnets. Th ese solitons are stabilized as a result of the conservation of various inte grals of motion: the z projection of the total spin S-z or the orbital angu lar momentum L-z of the magnetization field. A class of two-parameter solit ons with quite complicated (almost periodic) magnetization-field dynamics e xists for a purely uniaxial model (in the sense of both spin and spatial ro tations) with maximum symmetry. Stable solitons with periodic magnetization dynamics exist for ferromagnets with lower symmetry (only S-z or L-z or th e total angular momentum J(z) = L-z + S-z is conserved). (C) 1999 American Institute of Physics. [S1063-7761(99)02504-4].