VORTICES IN THE CONE PHASE OF A CLASSICAL QUASI-2-DIMENSIONAL FERROMAGNET

Vortex phenomenology is extended to the topological Berezinski-Kosterl itz-Thouless phase transition in the classical weakly anisotropic Heis enberg easy-plane ferromagnet, which is in magnetic field, directed al ong the hard axis of the magnet, in the so-called cone phase. Diminuti on of the critical temperature induced by the field is predicted. The static vortex structure in the external field is calculated. The field is shown to distinguish the properties of opposite polarized vortices and essentially influence the form of the components of the dynamic s tructural factor of the magnetic.