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. 2021 Apr 15;12:2272. doi: 10.1038/s41467-021-22515-3

Fig. 4. Calculated and observed structural spin-ice behaviour in Cd(CN)2.

Fig. 4

a Temperature-dependent population of CdCnN4–n coordination environments as determined by our MC pseudospin simulations (small symbols; error bars denote the standard error measured from five independent MC simulations), neutron PDF measurements (open squares) and 113Cd MAS NMR spectroscopic measurements (open circles), compared with the non-interacting analytical result (solid lines, ref. 34). The sublattice magnetisation (red symbols, red line)—or polarisation, in the specific context of Cd(CN)2—is an order parameter for the transition between the disordered (Pn3¯m) spin-ice state and the low-temperature (I41/amd) antiferroelectric state. b Variable-temperature 113Cd MAS NMR spectra (black lines) and corresponding fits (red lines) used to extract the values given in a. c Variable-temperature neutron PDF data (lower curves) and calculated PDFs from γ=0 and 23 QC configurations (upper curves) used to determine the PDF-derived values in a. d Single-crystal X-ray diffuse scattering pattern ((hk0) plane) measured at 298 K and calculated from a coupled CN-orientation/Cd-displacement model based on the 298 K pseudospin configuration. e Effective magnetic diffuse scattering pattern ((hhl) plane) extracted from our 300 K MC simulations by interpreting CN orientations from a single pyrochlore sublattice as classical spin vectors with the Dy3+ magnetic form factor (top panel). Calculated magnetic scattering for the pyrochlore Ising ferromagnet for the same relative temperature T/Jeff = 1.5 to which the Cd(CN)2 data correspond (bottom panel). In both cases, fluctuations away from the spin-ice ground state broaden the pinch-point features observed in experimental magnetic diffuse scattering pattern measured, for e.g., spin-ice Dy2Ti2O7 at 1.3 K68. Instead the scattering feature resemble more strongly the inelastic magnetic neutron scattering for strongly fluctuating spin-ice system such as Pr2Zr2O750.