LOCALIZED EXCITATIONS IN UPDSN

We have measured the inelastic-neutron-scattering response of UPdSn us ing 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 conducti on electrons. We also find a clear excitation around 40 meV above 40 K . This excitation may be indicative of localized crystal fields in UPd Sn, but its strong temperature dependence seems to contradict a simple crystal-held picture. Below T-N, an unusual temperature dependence ma y be attributed to magnetically driven distortions (and subsequent cha nges in the local surrounding of the U-ions), but there is some eviden ce that other additional mechanism(s) may contribute above T-N. (C) 19 98 Published by Elsevier Science B.V. All rights reserved.