Establishing magneto-structural relationships in the solid solutions of the skyrmion hosting family of materials: GaV${}_4$S${}_{8-y}$Se${}_y$

Abstract

The GaV${}_4$S${}_{8-y}$Se${}_y$ $(y=0$ to $8)$ family of materials have been synthesized in both polycrystalline and single crystal form, and their structural and magnetic properties thoroughly investigated. Each of these materials crystallizes in the $F\bar{4}3m$ space group at ambient temperature. However, in contrast to the end members GaV${}_4$S${}_8$ and GaV${}_4$Se${}_8$, that undergo a structural transition to the $R3m$ space group at 42 and 41 K respectively, the solid solutions $(y=1$ to $7)$ retain cubic symmetry down to 1.5 K. In zero applied field the end members of the family order ferromagnetically at 13 K (GaV${}_4$S${}_8$) and 18 K (GaV${}_4$Se${}_8$), while the intermediate compounds exhibit a spin-glass-like ground state. We demonstrate that the magnetic structure of GaV${}_4$S${}_8$ shows localization of spins on the V cations, indicating that a charge ordering mechanism drives the structural phase transition. We conclude that the observation of both structural and ferromagnetic transitions in the end members of the series in zero field is a prerequisite for the stabilization of a skyrmion phase, and discuss how the absence of these transitions in the $y=1$ to $7$ materials can be explained by their structural properties.

Main text: 14 pages, 5 figures, 1 table. Supplementary information: 10 pages, 6 figures, 6 tables

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Cited by in corpus (1)

• Structure and magnetism of the skyrmion hosting family GaV${}_4$S${}_{8-y}$Se${}_y$ with low levels of substitutions between $0\le y\le 0.5$ and $7.5\le y\le 8$