Robust metastable skyrmions and their triangular-square lattice structural transition in a high-temperature chiral magnet.

Abstract

Skyrmions, topologically protected nanometric spin vortices, are being investigated extensively in various magnets. Among them, many structurally chiral cubic magnets host the triangular-lattice skyrmion crystal (SkX) as the thermodynamic equilibrium state. However, this state exists only in a narrow temperature and magnetic-field region just below the magnetic transition temperature Tc, while a helical or conical magnetic state prevails at lower temperatures. Here we describe that for a room-temperature skyrmion material, β-Mn-type Co 8Zn 8Mn 4, a field-cooling via the equilibrium SkX state can suppress the transition to the helical or conical state, instead realizing robust metastable SkX states that survive over a very wide temperature and magnetic-field region. Furthermore, the lattice form of the metastable SkX is found to undergo reversible transitions between a conventional triangular lattice and a novel square lattice upon varying the temperature and magnetic field. These findings exemplify the topological robustness of the once-created skyrmions, and establish metastable skyrmion phases as a fertile ground for technological applications.

DOI: 10.1038/nmat4752

Cite this paper

@article{Karube2016RobustMS, title={Robust metastable skyrmions and their triangular-square lattice structural transition in a high-temperature chiral magnet.}, author={K Karube and J S White and Nigel Reynolds and Jorge Luis Gavilano and Hiroshi Oike and Akiko Kikkawa and Fumitaka Kagawa and Yusuke Tokunaga and Henrik Moodysson R\onnow and Yoshiki Tokura and Yoshio Taguchi}, journal={Nature materials}, year={2016}, volume={15 12}, pages={1237-1242} }