The lattice stiffening transition in UO2 single crystals

Authors

Christopher Young, Air Force Institute of Technology
James Petrosky, Air Force Institute of TechnologyFollow
J. Matthew Mann, Air Force Research Laboratory
Eric M. Hunt, Air Force Research Laboratory
David Turner, Air Force Research Laboratory
Peter A. Dowben, University of Nebraska-LincolnFollow

Date of this Version

2017

Citation

J. Phys.: Condens. Matter 29 (2017) 035005 (5pp)

Comments

© 2016 IOP Publishing Ltd

This document is a U.S. government work and is not subject to copyright in the United States.

doi:10.1088/1361-648X/29/3/035005

Abstract

The effective Debye temperatures (θ_DE) of the surface region of UO₂ single crystals, prepared by the hydrothermal synthesis technique, were obtained from temperature-dependent x-ray photoemission in the temperature range of 300 K–623 K. A lattice stiffening transition, characterized by different regions of different effective Debye temperature, 500 ± 59 K below 475 K and 165 ± 21 K above 475 K is identified. A comparison of the temperature dependence of the effective UO₂ Debye temperature, with the changes in the lattice expansion coefficient for UO₂, support strong lattice-phonon interaction arising from the Jahn–Teller distortion.