Approaching the Topological Low-Energy Physics of the F Model in a Two-Dimensional Magnetic Lattice
Résumé
We demonstrate that the physics of the F-model can be approached very closely in a twodimensional artificial magnetic system. Faraday lines spanning across the lattice and carrying a net polarization, together with chiral Faraday loops characterized by a zero magnetic susceptibility are imaged in real space using magnetic force microscopy. Our measurements reveal the proliferation of Faraday lines and Faraday loops as the system is brought from low-to high-energy magnetic configurations. They also reveal a link between the Faraday loop density and ice-like spin-spin correlations in the magnetic structure factor. Key for this work, the density of topological defects remains small, of the order of 1% or less, and negligible compared to the density of Faraday loops. This is made possible by replacing the spin degree of freedom used in conventional lattices of interacting nanomagnets by a micromagnetic knob, which can be finely tuned to adjust the vertex energy directly, rather than modifying the two-body interactions.
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