Quantum mechanics

Phase (matter)

Hexagonal lattice

Square lattice

Antiferromagnetism

Skyrmion

Crystal structure

Acoustics

Spins

Lattice (music)

Physics

Mathematics

Ising model

Tetragonal crystal system

Condensed matter physics

Combinatorics

Crystallography

Chemistry

Topology (electrical circuits)

Magnet

Spin structure

Nature

Crystal lattices with tetragonal or hexagonal structure often exhibit structural transitions in response to external stimuli1. Similar behaviour is anticipated for the lattice forms of topological spin textures, such as lattices composed of merons and antimerons or skyrmions and antiskyrmions (types of vortex related to the distribution of electron spins in a magnetic field), but has yet to be verified experimentally2,3. Here we report real-space observations of spin textures in a thin plate of the chiral-lattice magnet Co8Zn9Mn3, which exhibits in-plane magnetic anisotropy. The observations demonstrate the emergence of a two-dimensional square lattice of merons and antimerons from a helical state, and its transformation into a hexagonal lattice of skyrmions in the presence of a magnetic field at room temperature. Sequential observations with decreasing temperature reveal that the topologically protected skyrmions remain robust to changes in temperature, whereas the square lattice of merons and antimerons relaxes to non-topological in-plane spin helices, highlighting the different topological stabilities of merons, antimerons and skyrmions. Our results demonstrate the rich variety of topological spin textures and their lattice forms, and should stimulate further investigation of emergent electromagnetic properties. A magnetically induced two-dimensional square lattice of merons and antimerons is observed in real space, along with its transformation into a hexagonal lattice of skyrmions at room temperature.

Transformation between meron and skyrmion topological spin textures in a chiral magnet