Fig. 1: Crystal structure and magnetic map in Sr₆Ca₈Cu₂₄O₄₁ sample.

a Crystal structure of Sr₁₄Cu₂₄O₄₁ showing the alternating stack of CuO₂ chains (Cu in blue and O in red) and Cu₂O₃ ladder planes, separated by Sr ions (in green) along the b-axis. b [a,c] plane projection of the ladders subsystem including one two-leg ladder. The ladders are formed by edge-sharing CuO₂ squares. Mapping in momentum space of the full magnetic scattering deduced from XYZ-PA (c), and nuclear intensity measured in the non-spin-flip (NSF) channel (d) (measured on D7, T = 5K). The maps are given in reduced lattice unit (r.l.u.) of the ladders subsystem and the intensities in mbarn. The area bounded by dashed lines indicates the ladder scattering ridge along (H,0,1). The solid lines are associated with the chains nuclear response and blue crosses at integer H and L values correspond to the nuclear Bragg scattering associated with the ladders : c The ladders and satellite reflections magnetic spots are located by crosses and blue arrows, respectively. The magnetic satellite reflections are of the form (H, 0, − 1, 1) using 4D superspace notations. In d, the halos correspond to aluminum powder scattering from the sample holder. Sharper red spots in c located at positions of strong nuclear Bragg peaks in the NSF map (d) are not of magnetic origin but correspond to polarization leakages from the NSF channel.