Resonant x-ray spectroscopy of uranium intermetallics at the U M4,5 edges


Resonant x-ray spectroscopy of uranium intermetallics at the U M4,5 edges

Kvashnina, K. O.; Walker, H. C.; Magnani, N.; Lander, G. H.; Caciuffo, R.

We present resonant x-ray emission spectroscopic (RXES) data from the uranium intermetallics UPd3, USb, USn3 and URu2Si2 at the U M4,5 edges and compare the data to those from the well-localized 5f2 semiconductor UO2. The technique is especially sensitive to any oxidation of the surface, and this was found on the USb sample, thus preventing a good comparison with a material known to be 5f3. We have found a small energy shift between UO2 and UPd3, both known to have localized 5f2 configurations, which we ascribe to the effect of conduction electrons in UPd3. The spectra from UPd3 and URu2Si2 are similar, strongly suggesting a predominant 5f2 configuration for URu2Si2. The valence-band resonant inelastic x-ray scattering (RIXS) provides information on the U P3 transitions (at about 18 eV) between the U 5f and U 6p states, as well as transitions of between 3 and 7 eV from the valence band into the unoccupied 5f states. These transitions are primarily involving mixed ligand states (O 2p or Pd, Ru 4d) and U 5f states. Calculations are able to reproduce both these low-energy transitions reasonably well.

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Publ.-Id: 25118