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MA: Fachverband Magnetismus

MA 17: Multiferroics and Magnetoelectric Coupling (joint session MA/FM)

MA 17.9: Vortrag

Dienstag, 10. März 2026, 11:45–12:00, POT/0112

Towards topological switching in multiferroics — •Alessandro Granero and Sergey Artyukhin — Italian Institute of Technology (IIT), Genova, Italy

Magnetoelectric switching in GdMn2O5 [1] is the first known example of topological ferroic switching, where magnetic field sweeps across the spin-reorientation transition induce incremental 90^∘ spin rotations described by a topological winding number. While the behavior has been rationalized with a microscopic model, symmetry conditions and minimal model ingredients that enable this behavior are poorly understood. Here we use a symmetry-based Landau theory approach and demonstrate that a toy model with two frustrated antiferromagnetic subsystems and a low-symmetry anisotropy captures the topological switching behavior. The model reveals how sweeps of the driving field move the free-energy minimum continuously in spin-orientation space, in contrast to conventional ferroelectric switching that relies on fixed *P minima and domain-wall nucleation. Multiple switching pathways enabled by the simultaneous presence of E and H fields are summarized by a "switching diagram" [2], linking regions of the H and E field amplitudes to distinct sequences of magnetoelectric transitions. Small parameter variations near diagram boundaries redirect the system along different routes. The results establish a minimal model for topological switching in GdMn2O5 and guide the search for topological switching phenomena in other materials. [1] L. Ponet, et al.: Nature 607, 81-85 (2022) [2] M. Ryzhkov, A. Granero et al.: Communication Materials, in press

Keywords: multiferroics; topological switching; spin interactions; Landau theory; magnetoelectric coupling