Antiferromagnetic structure of UPd2Sb

We report the magnetic structure of the recently discovered mass enhanced antiferromagnet UPd2Sb, with an antiferromagnetic transition temperature of TN=55K. Our results have been obtained by analyzing the difference spectra of neutron scattering experiments carried out at low temperatures of 60 and 1.6K. Furthermore, the temperature dependence of the antiferromagnetically ordered moment has been determined. The antiferromagnetic phase consists of ferromagnetic planes spanned by two cubic axes of the Heusler lattice, which are antiferromagnetically coupled along the third axis. From a comparison of magnetic and structural peak intensity the ordered moment was determined to μord=1.3μB at zero temperature. The antiferromagnetic phase is characterized by a short magnetic correlation length of the order of 100Å, this as result of structural disorder in this compound.