Crystallographic and magnetic structure of UCu1.5Sn2

We report on the crystallographic and magnetic structures of the antiferromagnet UCu1.5Sn2, as determined by x-ray and neutron powder diffraction. It crystallizes in the tetragonal CaBe2Ge2 structure type, with space group P/4nmm, and we find no site disorder between two different Sn 2c sites, in contrast with a previous report. UCu1.5Sn2 orders antiferromagnetically with a Neel temperature of about 110 K. This is unusually high among uranium intermetallics. The uranium moments align along the c axis in a collinear arrangement but alternating along the c axis. The low-temperature uranium moment is 2.01 mu(B). (C) 1996 American Institute of Physics.