BROWN, P.J. ... et al, 1997. The structure and magnetic moment distribution in the antiferromagnetic phase of U14Au51. Journal of Physics: Condensed Matter, 9, pp. 4729–4742.
The antiferromagnetic structure of the intermetallic compound U14Au51 has been
determined from neutron polarimetric measurements and refined by combining these data with
integrated intensity measurements. The structure was found to be non-collinear with the U
moments confined to the a–b plane. The moments of U atoms in each of the two sets of
sixfold sites are arranged hexagonally with rotations of 60 between them and the two sets
are rotated with respect to one another by 50 . The third (twofold) set of U atoms has no
ordered moment. These conclusions are in disagreement with a previous determination of the
structure from powder data which gave a collinear structure with moments parallel to the c axis.
Magnetization measurements made on single crystals in the temperature range 300–2 K can
be understood in terms of a transition to a non-collinear easy plane antiferromagnetic structure
stable below 22 K. Polarized neutron measurements have been used to determine the contribution
of each of the U sites to the susceptibility between 22 and 2 K. These show that of the two
sixfold U sites, that with the smaller ordered moment contributes more than half of the total
susceptibility. The twofold site, which is characterized by a small U–U separation, makes the
This is Restricted Access. It is also available at: http://www.iop.org/Journals/S/3/211/cm .