Fig. 3 |. Momentum- and energy-resolved inelastic neutron scattering probing magnetic excitations in NaCaNi₂F₇.

a, Energy-momentum slices through the spin-flip portion of the polarized neutron scattering cross-section at $=1.8\mathrm{K}$. The data were symmetrized by folding about the line along $(0,0,\ell )$ for the $(2,2,\ell )$-energy slice and the line along $(h,h,0)$ for the $(h,h,2)$-energy slice. No smoothing or interpolation was applied to the data. b, Constant-momentum cuts of the spin-flip cross-section through a pinch point at $\mathbf{q}=(2,2,0)$ and nodal point at (2, 2, 1) integrated over $\ell \pm 0.2$. Solid lines are a fit to the sum of a Lorentzian function centred on the elastic line and a damped oscillator form $S(E)=\frac{(n+1)2\Gamma E}{{\left(E^2-E_q^2\right)}^2+(2\Gamma E{)}^2}$, where $n$ is the thermal population factor, $\mathrm{\Gamma }$ a relaxation rate and $E_q$ the characteristic energy scale. c, Constant-energy transfer cuts, integrated over $E\pm 0.25\mathrm{m}\mathrm{e}\mathrm{V}$, showing the energy evolution of momentum-dependent scattering, which becomes doubly peaked above 5 meV. Error bars represent one standard deviation.