Fig. 2: Details of the broken-helix magnetic order.
a Simulations of the magnetic neutron diffraction intensity for the (2, 0, 1) Bragg peak and the average of the (2, 0, 2) ± τ1 Bragg peaks as functions of the broken-helix turn angles ϕrb and ϕrr. b Temperature dependencies of the integrated intensity of the (2, 0, 1) Bragg peak and the average integrated intensity for the (2, 0, 2) ± τ1 magnetic Bragg peaks measured on the CORELLI spectrometer and scaled to 1 at T = 6 K. The inset displays the helix turn angles ϕ in the pure 60∘-helix phase (TN2 < T ≤ TN1) and ϕrb for the broken-helix phase (T ≤ TN2). c Temperature dependence of τ1 = (0, 0, τ1z) from the average of the positions of the (0, 0, 6) ± τ1 magnetic Bragg peaks. In b, ϕ(T) is calculated from the temperature evolution of τ1z. ϕrb(T) is calculated from the temperature dependence of the ratio of the integrated intensity of the (0, 0, 5) magnetic Bragg peak to that of the (006) − τ1 magnetic Bragg peak. These data are from measurements made on the TRIAX spectrometer and are shown in Supplementary Fig. 9.
