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Noise-induced switching between vortex states with different polarization in classical two-dimensional easy-plane magnets

Y. Gaididei·T. Kamppeter·F. G. Mertens·A. R. Bishop
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Abstract

In the 2-dimensional anisotropic Heisenberg model with XY-symmetry there are non-planar vortices which exhibit a localized structure of the z-components of the spins around the vortex center. We study how thermal noise induces a transition of this structure from one polarization to the opposite one. We describe the vortex core by a discrete Hamiltonian and consider a stationary solution of the Fokker-Planck equation. We find a bimodal distribution function and calculate the transition rate using Langer's instanton theory (1969). The result is compared with Langevin dynamics simulations for the full many-spin model.

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Y. Gaididei, T. Kamppeter, F. G. Mertens, A. R. Bishop. 1999-02-10. Noise-induced switching between vortex states with different polarization in classical two-dimensional easy-plane magnets. https://doi.org/10.1103/physrevb.59.7010

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