Fig. 3: Two spin components of the cone-type order in the ground state of DyTe₃ (Phase I).

In the geometry of Fig. 2d, non-spin-flip (NSF) and spin-flip (SF) neutron scattering measure the magnetic moment along the crystallographic a-axis and in the bc plane, respectively. a, b Polarization analysis of antiferromagnetic component q_AFM: absence of spin flip (SF) intensity indicates absence of m_b and m_c, while non-spin flip (NSF) intensity reveals dominant m_a. c, d Two views of the antiferromagnetic collinear component derived from this data, confirmed by full refinement of a number of magnetic reflections in Supplementary Fig. 8. Only Dy atoms are shown. e, f Polarization analysis for the incommensurate cycloidal reflection q_cyc. g Derived magnetic structure model for q_cyc, where m_a (NSF) vanishes while m_c and m_b (SF) both appear at comparable magnitudes in Phase I. The index j labels four dysprosium atoms in four layers within the chemical unit cell (red box), where the cycloids at j = 2, 4 are phase-shifted with respect to cycloids at j = 1, 3. The numerical value of δ is determined in Supplementary Section VI. As for a, b, e, f we have subtracted background signals, and corrected the effect of imperfect beam polarization. The error bars correspond to Poisson counting errors of the integrated neutron scattering intensity, given in counts per second (cps). Each inset depicts the orientation of the measured Q-vector within the (0KL) reciprocal space.