Dynamical skyrmions in Heisenberg two-dimensional easy-axis ferromagnets

The possibility of existence of dynamical skyrmions with high precession frequency (ω≥ω0, where ω0 is the resonance frequency) in the two-dimensional classical ferromagnets with easy-axis anisotropy is investigated analytically. The results show that at the resonance frequency, the structure of a skyrmion looks like a vortex having energy increasing logarithmically with the size of the system. For ω>ω0, the skyrmion has a diameter that depends on the competition between the easy-axis anisotropy and the dynamical term.