Structural and magnetic studies of the skyrmionic materials GaV₄S_8-ySe_y

There has been considerable interest in the magnetic skyrmions, their underlying physics, and the materials in which they are stabilised, due to their potential uses in spintronic devices. Magnetic skyrmions are topological magnetic spin structures that were originally identified in materials belonging to the B20 class but have recently been found in other non-centrosymmetric materials [1]. Both GaV₄S₈ and GaV₄Se₈ have been shown to host Néel type skyrmions [2]. These two materials are structurally similar, forming in a low temperature R3m non-centrosymmetric space group, but exhibit very different magnetic phase diagrams at low temperatures. We have undertaken investigations into the GaV₄S_8-ySe_y family of materials in order to identify the correlations between structure and magnetism across this series with a focus on magnetic skyrmions. We present detailed structural and magnetic property investigations using X-ray and neutron diffraction techniques, and both ac and dc magnetic susceptibility measurements across the entire series of materials [3,4].

[1] S. Mühlbauer, et al., Science 323, 915 (2009).
[2] I. Kézsmárki et al., Nat. Mater. 14, 4402 (2015).
[3] A. Štefančič et al., Sci. Rep. 10, 9813 (2020).
[4] S.J.R. Holt et al., arXiv:2010.13450 (2020).