By establishing magnetic order in a square lattice compound, we introduce the first magnetic “new fermion.”

${\mathrm{GdRu}}_2{\mathrm{Si}}_2$ is a centrosymmetric magnet in which a skyrmion lattice has recently been discovered. Here, we investigate the magnetic structure of the zero-field ground state using neutron diffraction on single crystal and polycrystalline ${{}^{160}\mathrm{GdRu}}_2{\mathrm{Si}}_2$. In addition to observing the principal propagation vectors ${\mathbf{q}}_1$ and ${\mathbf{q}}_2$, we discover higher-order magnetic satellites, notably ${\mathbf{q}}_1+2{\mathbf{q}}_2$. The appearance of these satellites is explained within the framework of a double-$Q$ constant-moment solution. Using powder diffraction, we implement a quantitative refinement of this model. This structure, which contains vortexlike motifs, is shown to have a one-dimensional topological charge density.

A helix of dipoles: In magnetic materials, magnetic dipoles typically line up parallel or antiparallel to each other. However, more complex orderings, such as helical, can also occur. Khalyavin et al. found that in the material BiCu _0.1 Mn _6.9 O ₁₂ , a helical order can be formed out of electric rather than magnetic dipoles. The material also harbors an associated structural helical order, which symmetry analysis suggests might be switchable with an applied electric field. Science , this issue p. 680