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arXiv · 1811.02337

Disordered skyrmion phase stabilized by magnetic frustration in a chiral magnet

K. Karube·J. S. White·D. Morikawa·C. D. Dewhurst·R. Cubitt·A. Kikkawa·X. Z. Yu·Y. Tokunaga·T. Arima·H. M. Rønnow·Y. Tokura·Y. Taguchi
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Abstract

Magnetic skyrmions are vortex-like topological spin textures often observed to form a triangular-lattice skyrmion crystal in structurally chiral magnets with Dzyaloshinskii-Moriya interaction. Recently $\beta$-Mn structure-type Co-Zn-Mn alloys were identified as a new class of chiral magnet to host such skyrmion crystal phases, while $\beta$-Mn itself is known as hosting an elemental geometrically frustrated spin liquid. Here we report the intermediate composition system Co$_7$Zn$_7$Mn$_6$ to be a unique host of two disconnected, thermal-equilibrium topological skyrmion phases; one is a conventional skyrmion crystal phase stabilized by thermal fluctuations and restricted to exist just below the magnetic transition temperature $T_\mathrm{c}$, and the other is a novel three-dimensionally disordered skyrmion phase that is stable well below $T_\mathrm{c}$. The stability of this new disordered skyrmion phase is due to a cooperative interplay between the chiral magnetism with Dzyaloshinskii-Moriya interaction and the frustrated magnetism inherent to $\beta$-Mn.

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K. Karube, J. S. White, D. Morikawa, C. D. Dewhurst, R. Cubitt, A. Kikkawa, X. Z. Yu, Y. Tokunaga, T. Arima, H. M. Rønnow, Y. Tokura, Y. Taguchi. 2018-11-06. Disordered skyrmion phase stabilized by magnetic frustration in a chiral magnet. https://doi.org/10.1112/s0010437x19007565

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