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arXiv · 1704.03621

Cycloidally modulated magnetic order stabilized by thermal fluctuations in the Néel-type skyrmion host GaV$_4$S$_8$

J. S. White·Á. Butykai·R. Cubitt·D. Honecker·C. D. Dewhurst·L. F. Kiss·V. Tsurkan·S. Bordács
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Abstract

We report small-angle neutron scattering studies of the lacunar spinel GaV$_4$S$_8$, which reveal the long-wavelength magnetic states to be cycloidally modulated. This provides direct support for the formation of Néel-type skyrmions recently claimed to exist in this compound. In striking contrast with all other bulk skyrmion host materials, upon cooling the modulated magnetic states transform into a ferromagnetic state. These results indicate all of the modulated states in GaV$_4$S$_8$, including the skyrmion state, gain their stability from thermal fluctuations, while at lower temperature the ferromagnetic state emerges in accord with the strong easy-axis magnetic anisotropy. In the vicinity of the transition between the ferromagnetic and modulated states, both a phase coexistence and a soliton-like state are also evidenced by our study.

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J. S. White, Á. Butykai, R. Cubitt, D. Honecker, C. D. Dewhurst, L. F. Kiss, V. Tsurkan, S. Bordács. 2017-04-12. Cycloidally modulated magnetic order stabilized by thermal fluctuations in the Néel-type skyrmion host GaV$_4$S$_8$. https://doi.org/10.1103/physrevb.97.020401

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