| Autor: |
Leonov AO; Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden (IFW Dresden), Helmholtzstraße 20, D-01069 Dresden, Germany.; Department of Chemistry, Faculty of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Hiroshima, Japan.; International Institute for Sustainability with Knotted Chiral Meta Matter, Kagamiyama, Higashi-Hiroshima 739-8511, Hiroshima, Japan., Rößler UK; Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden (IFW Dresden), Helmholtzstraße 20, D-01069 Dresden, Germany. |
| Abstrakt: |
Isolated chiral skyrmions are investigated within the phenomenological Dzyaloshinskii model near the ordering temperatures of quasi-two-dimensional chiral magnets with Cnv symmetry and three-dimensional cubic helimagnets. In the former case, isolated skyrmions (IS) perfectly blend into the homogeneously magnetized state. The interaction between these particle-like states, being repulsive in a broad low-temperature (LT) range, is found to switch into attraction at high temperatures (HT). This leads to a remarkable confinement effect: near the ordering temperature, skyrmions exist only as bound states. This is a consequence of the coupling between the magnitude and the angular part of the order parameter, which becomes pronounced at HT. The nascent conical state in bulk cubic helimagnets, on the contrary, is shown to shape skyrmion internal structure and to substantiate the attraction between them. Although the attracting skyrmion interaction in this case is explained by the reduction of the total pair energy due to the overlap of skyrmion shells, which are circular domain boundaries with the positive energy density formed with respect to the surrounding host phase, additional magnetization "ripples" at the skyrmion outskirt may lead to attraction also at larger length scales. The present work provides fundamental insights into the mechanism for complex mesophase formation near the ordering temperatures and constitutes a first step to explain the phenomenon of multifarious precursor effects in that temperature region. |
