UPd3 is known to exhibit four antiferroquadrupolar ordered phases at low
temperatures. We report measurements of the magnetisation and magnetostriction
of single crystal UPd3, along the principal symmetry directions, in fields
up to 33 T. These results have been combined with recent inelastic neutron and
x-ray resonant scattering measurements to construct a mean field model of
UPd3 including up to fourth nearest neighbour interactions. In particular we
find that anisotropic quadrupolar interactions must be included in order to
explain the low temperature structures derived from the scattering data.Comment: 9 pages, 6 figures, 3 table