Neutron-Diffraction Studies of Single Crystals of U2T2In (T = Ni, Pd, Pt).

Neutron-diffraction experiments on single crystals of ${\mathrm{U}}_{2}{T}_{2}\mathrm{In} (T=\mathrm{Ni},$ Pd, Pt) verify the noncollinear magnetic structures found with studies of polycrystalline samples, and determine the values of the ordered moments. Compared to the earlier studies, we find the ordered moments on the uranium atoms larger, and no moment associated with the T atoms, in disagreement with one previous study. The $T=\mathrm{Pt}$ sample has a large electronic specific heat and does not order magnetically. We give a detailed description of the low-temperature crystal structure. Polarized-neutron experiments show that the site susceptibilities of the two independent uranium atoms in ${\mathrm{U}}_{2}{\mathrm{Pt}}_{2}\mathrm{In}$ are substantially different and the conduction-electron polarization is unusually large.