Robust noncoplanar magnetism in band-filling-tuned ( Nd1?xCax)2Mo2O7

In the metallic pyrochlore ${\mathrm{Nd}}_{2}{\mathrm{Mo}}_{2}{\mathrm{O}}_{7}$, conducting molybdenum sublattice adopts canted, yet nearly collinear, ferromagnetic order with nonzero scalar spin chirality. The chemical potential may be controlled by replacing ${\mathrm{Nd}}^{3+}$ ${\mathrm{Ca}}^{2+}$, while introducing only minimal additional disorder to states. Here, we demonstrate stability of canted state, including tilting angle spins, in (${\mathrm{Nd}}_{1\ensuremath{-}x}{\mathrm{Ca}}_{x}$)${}_{2}{\mathrm{Mo}}_{2}{\mathrm{O}}_{7}$ $x\ensuremath{\le}0.15$ using magnetic susceptibility measurements. Mo-Mo and Mo-Nd couplings both change sign above $x=0.22$, where state gives way a spin-glass region. Contributions Curie-Weiss law from two species are separated systematically.