Anisotropy-driven response of the fractional antiferromagnetic skyrmion lattice in MnSc2S4 to applied magnetic fields

Abstract

We theoretically and experimentally study the stability of the unconventional fractional antiferromagnetic skyrmion lattice (AF-SkL) in ${\mathrm{MnSc}}_{2}{\mathrm{S}}_{4}$ spinel under magnetic fields applied along the [1-10] crystal direction. By performing numerical Monte Carlo simulations for the minimal effective spin model that we proposed in S. Gao et al., Nature 586, 37 (2020), we show that the lattice is aligned within the equivalent and symmetric [1-11] or [1-1-1] planes, which are equally inclined to the applied magnetic-field $H$. We attribute this behavior to the magnetic anisotropy of the host material. Neutron single-crystal diffraction presents a very good agreement with the predictions of the effective model. It reveals that the topological spin texture gets destabilized at low temperatures and moderate magnetic fields and is replaced by a conical phase for $H$// [1-10]. The present study elucidates the central role of the magnetic anisotropy in the stabilization of AF-Sk states.