Experiment and theory indicate that UPt3 is a topological superconductor in an odd-parity state, based in part from temperature independence of the NMR Knight shift. However, quasiparticle spin-flip scattering near a surface, where the Knight shift is measured, might be responsible. We use polarized neutron scattering to measure the bulk susceptibility with H||c, finding consistency with the Knight shift but inconsistent with theory for this field orientation. We infer that neither spin susceptibility nor Knight shift are a reliable indication of odd-parity.
@article{arxiv.1705.08098,
title = {Spin Susceptibility of the Topological Superconductor UPt3 from Polarized Neutron Diffraction},
author = {W. J. Gannon and W. P. Halperin and M. R. Eskildsen and Pengcheng Dai and U. B. Hansen and K. Lefmann and A. Stunault},
journal= {arXiv preprint arXiv:1705.08098},
year = {2017}
}