Localized excitations in UPdSn

We have measured the inelastic-neutron-scattering response of UPdSn using the HET and PHAROS spectrometers at the ISIS and LANSCE facilities, respectively. UPdSn shows some quasielastic scattering, which may be attributed to the hybridization of the Sf-electrons with the conduction electrons. We also find a clear excitation around 40 meV above 40 K. This excitation may be indicative of localized crystal fields in UPdSn, but its strong temperature dependence seems to contradict a simple crystal-held picture. Below T-N, an unusual temperature dependence may be attributed to magnetically driven distortions (and subsequent changes in the local surrounding of the U-ions), but there is some evidence that other additional mechanism(s) may contribute above T-N. (C) 1998 Published by Elsevier Science B.V. All rights reserved.