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Neutron scattering studies of the structures and Vibrational Dynamics of the HCP Rare-Earth Trihydrides

Published online by Cambridge University Press:  10 February 2011

T. J. Udovic
Affiliation:
NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
Q. Huang
Affiliation:
also at the Department of Materials and Nuclear Engineering, University of Maryland, College Park, MD 20742
J. J. Rush
Affiliation:
NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899
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Abstract

Both neutron-powder-diffraction and neutron-vibrational-spectroscopy studies have been undertaken to characterize the structures and vibrational dynamics of a variety of bulk hcp rareearth trihydrides RH3 (where R = Y, Th, Dy, Ho, Er, and Lu). The results are consistent with P3c1 as the prevalent structural symmetry for all trihydrides investigated except LuH3. Corresponding results for LuH3 are suggestive of an atypical arrangement of H atoms. Preliminary analyses of LuD3 diffraction patterns indicate that the main peaks can be satisfactorily modeled using P63/mmc symmetry with a reduced unit cell, although numerous minor diffraction features and a relatively unusual vibrational spectrum hint at either a more complex structure or an unknown secondary phase. The deviations from P3c1 symmetry are likely a consequence of the relatively smaller metal-hydrogen bond distances for LuH3.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

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