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Durham University

Department of Physics

Staff profile

Publication details for Professor Tom Lancaster

Štefančič, Aleš, Holt, Samuel J. R., Lees, Martin R., Ritter, Clemens, Gutmann, Matthias J., Lancaster, Tom & Balakrishnan, Geetha (2020). Establishing magneto-structural relationships in the solid solutions of the skyrmion hosting family of materials: GaV4S8−ySey. Scientific Reports 10(1): 9813.

Author(s) from Durham

Abstract

The GaV4S8−ySey (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 Fˉ
43m space group at ambient temperature. However, in contrast to the end
members GaV4S8 and GaV4Se8, 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 feld
the end members of the family order ferromagnetically at 13 K (GaV4S8) and 18 K (GaV4Se8), while the
intermediate compounds exhibit a spin-glass-like ground state. We demonstrate that the magnetic
structure of GaV4S8 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 feld 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.