Universality scaling study of Néel-type skyrmion host GaV<sub>4</sub>S<sub>8</sub> single crystal

Lacunar spinel GaV4S8 is a crucial material for spintronic applications due to its emergent rare Néel-type skyrmions and unique orbitally-driven ferroelectric polarization. Nevertheless, persistent debates surround its magnetic properties and ground state, espcially in single crystals. In this study, we systematically investigate the anisotropic magnetism and phase diagrams of single-crystal GaV4S8 by combining magnetic entropy analysis and universality scaling laws. The critical exponents for single-crystal GaV4S8 are determined to be β=0.434(5), γ=1.768(3), and δ=5.025(1) at critical temperature TC=12.9(1) K. These exponents cannot be classified into any conventional universality class, indicating the coexistence of multiple magnetic interactions within this material. Utilizing universality scaling, we construct phase diagrams of single-crystal GaV4S8 for three distinct field orientations: H//[111], H//[110], and H//[100]. For H//[111] corresponding to the easy magnetic axis, the spin dimensionality analysis indicates a short-range interaction that follows J(r)∼r−5.21(4). Moreover, the phase diagrams reveal various magnetic phases, particularly a ground state of a possible cluster spin-glass in all directions. These findings elucidate the intricate magnetic interactions in single-crystal GaV4S8, which are crucial for understanding the formation of diverse non-collinear spin-ordered phases and potential applications in this system.