Oscillating spin vortices in a two-sublattice uniaxial antiferromagnet

A distribution of the antiferromagnetic vector in a uniaxial two-sublattice antiferromagnet is investigated. A new class of nonlinear solutions of the system of two well-known Landau–Lifshitz equations in the form of so called nonlinear sigma-model is obtained and a new type of topological magnetic configuration in the investigated antiferromagnet is described. Examples of solutions of the found class are presented. These examples include vortex-like structures, both moving and static. It is assumed that such vortices have an oscillating nature, so that the angle between the antiferromagnetic vector and the magnetic symmetry axis oscillates with descending amplitude and tends to π/2 when the distance to the vortex axis increases. (author)