Extended Data Fig. 2: Polarized neutron scattering experiments and estimation of the strength of the single-ion anisotropy K.
From: Emergent electric field induced by dissipative sliding dynamics of domain walls in a Weyl magnet
a, Measurement geometry for polarized neutron scattering. The intensities of the non-spin-flip (NSF) and spin-flip (SF) channels are related to the c-axis moment and to the moment in the ab-plane perpendicular to the Q-vector, respectively: \({I}_{{{\rm{NSF}}}}\propto {{M}^{2}}_{{{\rm{c}}}}\) and \({I}_{{{\rm{SF}}}}\propto {\mid{M}^{\perp }}_{{{\rm{in}}}}( Q)\mid^{2}\). b,c, Magnetic reflections observed at Q1/3 = (1/3 + δ1, 1/3 + δ1, 0) and Q2/3 = (2/3 + δ2, 2/3 + δ2, 0) in the incommensurate phase at 5 K, where δ1 ≠0 and δ2 ≠0. d,e, Magnetic reflections observed at Q1/3 and Q2/3 in the commensurate phase at 2.5 K, where δ1 and δ2 are nearly zero. The large ISF at Q1/3 indicates that the dominant contribution of the magnetic moment related to Q1/3 is in the ab-plane, while Mc is dominant for the Q2/3 modulation. f, Noncollinear ferrimagnetic order of NdAlSi with the in-plane magnetization component perpendicular to the Q-vector27,51. g, Definition of the spin tilt angle η of the noncollinear ferrimagnetic order (Supplementary Notes 7 and 8 and Ref. 51). h, Noncollinear ferrimagnetic order of NdAlSi in our one-dimensional spin model. i, Definition of the spin tilt angle \({\eta }^{{\prime} }\) in our spin model. j, Calculated \({\eta }^{{\prime} }\) as a function of the ratio of single-ion anisotropy K to the exchange interaction J. The experimental value of the relative angle (η ~ 20 degrees) can be reproduced by a modest value of K/J between 0.05 and 0.2.
