Topological transitions among skyrmion- and hedgehog-lattice states in cubic chiral magnets

TLDR

Manipulating topological spin textures is key to exploring emergent electromagnetic phenomena, yet transitions between distinct topological orders remain largely unexplored. The authors develop a series of chiral magnets MnSi₁₋ₓGeₓ as a platform to study transitions between skyrmion‑ and hedgehog‑lattice states. Using neutron scattering, Lorentz TEM, and high‑field transport, they observe three topological spin textures whose lattice constants vary with Si/Ge substitution. The appearance of multiple topological spin states under chemical pressure indicates a new route for mechanically manipulating spin‑texture topology.

Abstract

Abstract Manipulating topological spin textures is a key for exploring unprecedented emergent electromagnetic phenomena. Whereas switching control of magnetic skyrmions, e.g., the transitions between a skyrmion-lattice phase and conventional magnetic orders, is intensively studied towards development of future memory device concepts, transitions among spin textures with different topological orders remain largely unexplored. Here we develop a series of chiral magnets MnSi 1− x Ge x , serving as a platform for transitions among skyrmion- and hedgehog-lattice states. By neutron scattering, Lorentz transmission electron microscopy and high-field transport measurements, we observe three different topological spin textures with variation of the lattice constant controlled by Si/Ge substitution: two-dimensional skyrmion lattice in x = 0–0.25 and two distinct three-dimensional hedgehog lattices in x = 0.3–0.6 and x = 0.7–1. The emergence of various topological spin states in the chemical-pressure-controlled materials suggests a new route for direct manipulation of the spin-texture topology by facile mechanical methods.