Fig. 4

Magnetic order and phase diagram of Yb₂Pt₂Pb. a–d. Time of flight data with energy transfer E = 0 in the q_HH, q_L plane, measured at T = 0.1 K in fields of 0.025 T (a), 0.75 T (b), 1.2 T (c), and 1.7 T (d). The magnetic Bragg diffraction peaks in each part of the phase diagram are labeled 1–4. (e, f) The location in reciprocal space along q_L (e) and q_HH (f) of the magnetic Bragg scattering as a function of the field in the regions plotted in parts a–d. Data shown are an average, symmetrized about q_L = 1 and q_HH = 0. The open symbols correspond to the peaks labeled 1-4 in panels b–e, with black indicating peak 1, blue peak 2, red peak 3, and green peak 4. Magnetization divided by the saturation magnetization M/M_sat as a function of the field along the (110) crystal direction is also shown in panel e (pink line, right axis), demonstrating the initial trend, M/M_sat ≈ (q_L − 1) and the concurrence of the jumps in magnetization with the abrupt changes in the position of elastic scattering. (g) The intensity of the diffraction peaks in parts b–f. The AFM order that emerges for μ₀H > 1 T is considerably weaker than the low field order, while the low field order falls off very abruptly for μ₀H > 1.2 T. Symbols are the same as in panels e, f. (h) The zero field magnetic structure and dipole interactions in Yb₂Pt₂Pb. Yb moments in five unit cells are shown along the diagonal, (110) direction, with the interchain couplings, \({\cal J}_n^ \bot\), as indicated. The Yb SSL AFM layers are highlighted (blue and green arrows), with the periodicity given by FM pairs every five unit cells (black and red arrows)