We discuss possible magnetic structures in UPt3 based on our analysis of elastic neutron-scattering experiments in high magnetic fields at temperatures T<TN. The existing experimental data can be explained by a single-{\bf q} antiferromagnetic structure with three independent domains. For modest in-plane spin-orbit interactions, the Zeeman coupling between the antiferromagnetic order parameter and the magnetic field induces a rotation of the magnetic moments, but not an adjustment of the propagation vector of the magnetic order. A triple-{\bf q} magnetic structure is also consistent with neutron experiments, but in general leads to a non-uniform magnetization in the crystal. New experiments could decide between these structures.
@article{arxiv.cond-mat/0004253,
title = {Magnetic Field Effects on Neutron Diffraction in the Antiferromagnetic Phase of $UPt_3$},
author = {Juana Moreno and J. A. Sauls},
journal= {arXiv preprint arXiv:cond-mat/0004253},
year = {2009}
}