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Title: High pressure and temperature equation of state and spectroscopic study of CeO2

One of the most widely used x-ray standards and a highly applied component of catalysis systems, CeO2 has been studied for the purpose of better understanding its equation of state and electronic properties. Diamond anvil cells have been used to extend the equation of state for this material to 130 GPa and explore the electronic behavior with applied load. From the x-ray diffraction studies, it has been determined that the high pressure phase transition extends from approximately 35–75 GPa at ambient temperature. Elevation of temperature is found to decrease the initiation pressure for this transition, with multiple distinct temperature regions which indicate structural related anomalies. In addition, hydrostatic and non-hydrostatic effects are compared and exhibit a drastic difference in bulk moduli. Furthermore, the electronic results indicate a change in the scattering environment of the cerium atom, associated with the high pressure phase transition. Overall, these results present the first megabar pressure study and the first high pressure and temperature study of ceria. Additionally, this shows the first combined study of the K and LIII edges of this material to 33 GPa.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Carnegie Institute of Washington, Argonne, IL (United States)
Publication Date:
OSTI Identifier:
1242313
Report Number(s):
LA-UR-15-25295
Journal ID: ISSN 0953-8984
Grant/Contract Number:
EAR1128799; EAR1157758; AC02-06CH11357; AC52-06NA25396; FG02-94ER14466; FG02-99ER45775; NA0001974
Type:
Published Article
Journal Name:
Journal of Physics. Condensed Matter
Additional Journal Information:
Journal Volume: 28; Journal Issue: 15; Journal ID: ISSN 0953-8984
Publisher:
IOP Publishing
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ceria; high pressure; equation of state; spectroscopy