We report magnetic, transport, specific-heat and neutron-diffraction m
easurements on UPt2In. The results indicate that UPt2In orders antifer
romagnetically below 35 K and undergoes another magnetic transition at
15 K. Even below 15 K, the intensity of an antiferromagnetic neutron
reflection of d = 6.57 Angstrom continues to increase. The magnetizati
on curve at 4.2 K exhibits a spontaneous moment of 0.2 mu(B)/f.u. and
a metamagnetic transition at 24 T. A rather large specific-heat coeffi
cient C/T of 100 mJ/K-2 mol remains at 1.4 K.