Scalar Chiral Spin-1/2 Order on Kagome Lattices in Nd3Sb3Mg2O14

We introduce $\mathrm{N}{\mathrm{d}}_3\mathrm{S}{\mathrm{b}}_3\mathrm{M}{\mathrm{g}}_2{\mathrm{O}}_{14}$ with ideal kagome lattices of neodymium ions in ABC stacking. Thermodynamic measurements show a Curie-Weiss temperature of ${\mathrm{\Theta }}_{CW}=-0.12$K, a Nd${}^{3+}$ spin-1/2 Kramers doublet ground state, and a second order phase transition at $T_N=0.56(2)$K. Neutron scattering reveals non-coplanar scalar chiral $\mathbf{k}=0$ magnetic order with a correlation length exceeding 400 \AA = 55 $a$ and an ordered moment of $1.79(5){\mu }_B$. This order includes a canted ferromagnetic component perpendicular to the kagome planes favored by Dzyaloshinskii-Moriya interactions.