skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Probing disorder in pyrochlore oxides using in situ synchrotron diffraction from levitated solids–A thermodynamic perspective

Abstract

Pyrochlore, an ordered derivative of the defect fluorite structure, shows complex disordering behavior as a function of composition, temperature, pressure, and radiation damage. We propose a thermodynamic model to calculate the disordering enthalpies for several RE2Zr2O7 (RE = Sm, Eu, Gd) pyrochlores from experimental site distribution data obtained by in situ high temperature synchrotron X-ray diffraction. Site occupancies show a gradual increase in disorder on both cation and anion sublattices with increasing temperature and even greater disorder is achieved close to the phase transition to defect fluorite. The enthalpy associated with cation disorder depends on the radius of the rare earth ion, while the enthalpy of oxygen disordering is relatively constant for different compositions. The experimental data support trends predicted by ab initio calculations, but the obtained enthalpies of disordering are less endothermic than the predicted values. Thermal expansion coefficients are in the range (8.6-10.8) x 10-6 K-1. These new experimental determinations of defect formation energies are important for understanding the stability of pyrochlore oxides and their disordering mechanisms, which are essential in the context of their potential applications in nuclear waste management and other technologies.

Authors:
ORCiD logo; ORCiD logo; ; ; ORCiD logo
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1459466
Alternate Identifier(s):
OSTI ID: 1480857
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Published Article
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Name: Scientific Reports Journal Volume: 8 Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United Kingdom
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE

Citation Formats

Maram, Pardha S., Ushakov, Sergey V., Weber, Richard J. K., Benmore, Chris J., and Navrotsky, Alexandra. Probing disorder in pyrochlore oxides using in situ synchrotron diffraction from levitated solids–A thermodynamic perspective. United Kingdom: N. p., 2018. Web. doi:10.1038/s41598-018-28877-x.
Maram, Pardha S., Ushakov, Sergey V., Weber, Richard J. K., Benmore, Chris J., & Navrotsky, Alexandra. Probing disorder in pyrochlore oxides using in situ synchrotron diffraction from levitated solids–A thermodynamic perspective. United Kingdom. doi:https://doi.org/10.1038/s41598-018-28877-x
Maram, Pardha S., Ushakov, Sergey V., Weber, Richard J. K., Benmore, Chris J., and Navrotsky, Alexandra. Fri . "Probing disorder in pyrochlore oxides using in situ synchrotron diffraction from levitated solids–A thermodynamic perspective". United Kingdom. doi:https://doi.org/10.1038/s41598-018-28877-x.
@article{osti_1459466,
title = {Probing disorder in pyrochlore oxides using in situ synchrotron diffraction from levitated solids–A thermodynamic perspective},
author = {Maram, Pardha S. and Ushakov, Sergey V. and Weber, Richard J. K. and Benmore, Chris J. and Navrotsky, Alexandra},
abstractNote = {Pyrochlore, an ordered derivative of the defect fluorite structure, shows complex disordering behavior as a function of composition, temperature, pressure, and radiation damage. We propose a thermodynamic model to calculate the disordering enthalpies for several RE2Zr2O7 (RE = Sm, Eu, Gd) pyrochlores from experimental site distribution data obtained by in situ high temperature synchrotron X-ray diffraction. Site occupancies show a gradual increase in disorder on both cation and anion sublattices with increasing temperature and even greater disorder is achieved close to the phase transition to defect fluorite. The enthalpy associated with cation disorder depends on the radius of the rare earth ion, while the enthalpy of oxygen disordering is relatively constant for different compositions. The experimental data support trends predicted by ab initio calculations, but the obtained enthalpies of disordering are less endothermic than the predicted values. Thermal expansion coefficients are in the range (8.6-10.8) x 10-6 K-1. These new experimental determinations of defect formation energies are important for understanding the stability of pyrochlore oxides and their disordering mechanisms, which are essential in the context of their potential applications in nuclear waste management and other technologies.},
doi = {10.1038/s41598-018-28877-x},
journal = {Scientific Reports},
number = 1,
volume = 8,
place = {United Kingdom},
year = {2018},
month = {7}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: https://doi.org/10.1038/s41598-018-28877-x

Citation Metrics:
Cited by: 4 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Aero‐acoustic levitation: A method for containerless liquid‐phase processing at high temperatures
journal, February 1994

  • Weber, J. K. Richard; Hampton, D. Scott; Merkley, Dennis R.
  • Review of Scientific Instruments, Vol. 65, Issue 2
  • DOI: 10.1063/1.1145157

Similar local order in disordered fluorite and aperiodic pyrochlore structures
journal, February 2018


Drop-and-catch (DnC) calorimetry using aerodynamic levitation and laser heating
journal, October 2016

  • Ushakov, Sergey V.; Shvarev, Alexey; Alexeev, Timur
  • Journal of the American Ceramic Society, Vol. 100, Issue 2
  • DOI: 10.1111/jace.14594

Thermal Conductivity and Thermal Expansion Coefficients of the Lanthanum Rare-Earth-Element Zirconate System
journal, August 2003


Direct Measurement of Surface Dissolution Rates in Potential Nuclear Waste Forms: The Example of Pyrochlore
journal, August 2015

  • Fischer, Cornelius; Finkeldei, Sarah; Brandt, Felix
  • ACS Applied Materials & Interfaces, Vol. 7, Issue 32
  • DOI: 10.1021/acsami.5b04281

Disorder in Pyrochlore Oxides
journal, August 2000


Nuclear wasteform materials: Atomistic simulation case studies
journal, October 2013


Defects and diffusion in pyrochlore structured oxides
journal, October 1998


Theoretical study of disorder in Ti-substituted La 2 Zr 2 O 7
journal, March 2002


Effects of the synthesis procedure, doping and non-stoichiometry on the order–disorder transformation in LnTiO (Ln=Tm–Lu) oxygen-ion conductors
journal, September 2005


The thermodynamics of cation distributions in simple spinels
journal, November 1967


Aerodynamic levitator for in situ x-ray structure measurements on high temperature and molten nuclear fuel materials
journal, July 2016

  • Weber, J. K. R.; Tamalonis, A.; Benmore, C. J.
  • Review of Scientific Instruments, Vol. 87, Issue 7
  • DOI: 10.1063/1.4955210

Synthesis of a metallic mesoporous pyrochlore as a catalyst for lithium–O2 batteries
journal, November 2012

  • Oh, Si Hyoung; Black, Robert; Pomerantseva, Ekaterina
  • Nature Chemistry, Vol. 4, Issue 12, p. 1004-1010
  • DOI: 10.1038/nchem.1499

Ionic Conductivity of Ln2 + x Zr2 − x O7 − x/2 (Ln = Sm-Gd) Solid Solutions
journal, August 2005


Fluorite-pyrochlore transformation in Eu2Zr2O7—direct calorimetric measurement of phase transition, formation and surface enthalpies
journal, January 2012

  • Saradhi, M. P.; Ushakov, S. V.; Navrotsky, A.
  • RSC Advances, Vol. 2, Issue 8
  • DOI: 10.1039/c2ra00727d

In Situ Diffraction from Levitated Solids Under Extreme Conditions—Structure and Thermal Expansion in the Eu 2 O 3 –ZrO 2 System
journal, December 2014

  • Maram, Pardha S.; Ushakov, Sergey V.; Weber, Richard J. K.
  • Journal of the American Ceramic Society, Vol. 98, Issue 4
  • DOI: 10.1111/jace.13422

Etude de la transformation ordre-desordre de la structure fluorite a la structure pyrochlore pour des phases (1−x) ZrO2  x Ln2O3
journal, November 1974


First-principles calculation of defect-formation energies in the Y 2 ( Ti , Sn , Zr ) 2 O 7 pyrochlore
journal, August 2004


Defect formation energies in A 2 B 2 O 7 pyrochlores
journal, October 2015


Structure and Thermal Expansion of YSZ and La 2 Zr 2 O 7 Above 1500°C from Neutron Diffraction on Levitated Samples
journal, July 2015

  • Ushakov, Sergey V.; Navrotsky, Alexandra; Weber, Richard J. K.
  • Journal of the American Ceramic Society, Vol. 98, Issue 10
  • DOI: 10.1111/jace.13767

Role of Antisite Disorder on Preamorphization Swelling in Titanate Pyrochlores
journal, May 2012


Effect of non-stoichiometry and synthesis temperature on the structure and conductivity of Ln2+xM2−xO7−x/2 (Ln=Sm–Gd; M=Zr, Hf; x=0–0.286)☆
journal, January 2007


Atomic disorder in Gd 2 Zr 2 O 7 pyrochlore
journal, May 2015

  • Zhang, F. X.; Lang, M.; Ewing, R. C.
  • Applied Physics Letters, Vol. 106, Issue 19
  • DOI: 10.1063/1.4921268

Levitation apparatus for structural studies of high temperature liquids using synchrotron radiation
journal, September 1997

  • Krishnan, Shankar; Felten, John J.; Rix, James E.
  • Review of Scientific Instruments, Vol. 68, Issue 9
  • DOI: 10.1063/1.1148315

Radiation-induced amorphization resistance and radiation tolerance in structurally related oxides
journal, February 2007

  • Sickafus, Kurt E.; Grimes, Robin W.; Valdez, James A.
  • Nature Materials, Vol. 6, Issue 3
  • DOI: 10.1038/nmat1842

Oxide pyrochlores — A review
journal, January 1983

  • Subramanian, M. A.; Aravamudan, G.; Subba Rao, G. V.
  • Progress in Solid State Chemistry, Vol. 15, Issue 2
  • DOI: 10.1016/0079-6786(83)90001-8

Intricate disorder in defect fluorite/pyrochlore: a concord of chemistry and crystallography
journal, June 2017


Heat capacity for the Eu2Zr2O7 and phase relations in the ZrO2–Eu2O3 system: Experimental studies and calculations
journal, April 2013


Structure and thermal expansion of Lu2O3 and Yb2O3 up to the melting points
journal, November 2017


Pressure-induced structural modifications of rare-earth hafnate pyrochlore
journal, May 2017

  • Turner, Katlyn M.; Rittman, Dylan R.; Heymach, Rachel A.
  • Journal of Physics: Condensed Matter, Vol. 29, Issue 25
  • DOI: 10.1088/1361-648X/aa7148

First-principles calculation of defect formation energies and electronic properties in stannate pyrochlores
journal, November 2008

  • Chen, Z. J.; Xiao, H. Y.; Zu, X. T.
  • Journal of Applied Physics, Vol. 104, Issue 9
  • DOI: 10.1063/1.3000558

Radiation Tolerance of Complex Oxides
journal, August 2000


A profile refinement method for nuclear and magnetic structures
journal, June 1969


Nuclear waste disposal—pyrochlore (A2B2O7): Nuclear waste form for the immobilization of plutonium and “minor” actinides
journal, June 2004

  • Ewing, Rodney C.; Weber, William J.; Lian, Jie
  • Journal of Applied Physics, Vol. 95, Issue 11
  • DOI: 10.1063/1.1707213

Ionic conduction in the Gd2Ti2O7−Gd2Zr2O7 system
journal, September 1988


Thermochemistry of lanthanum zirconate pyrochlore
journal, November 2009

  • Radha, A. V.; Ushakov, Sergey V.; Navrotsky, Alexandra
  • Journal of Materials Research, Vol. 24, Issue 11
  • DOI: 10.1557/jmr.2009.0401

Order–Disorder Transformations in Ln 2 Ti 2 O 7 (Ln = Lu, Yb, Tm, Gd)
journal, January 2004


Neutron Powder Diffraction Studies of Fluorite and Pyrochlore NdxZr1−xO2−x/2 Solid Solutions with 0.25<x<0.55
journal, October 1980

  • Van Dijk, T.; Helmholdt, R. B.; Burggraaf, A. J.
  • physica status solidi (b), Vol. 101, Issue 2
  • DOI: 10.1002/pssb.2221010239

Intricate disorder
journal, February 2016


Thermal expansion behaviour of some rare earth oxide pyrochlores
journal, July 1994


Whole powder pattern decomposition methods and applications: A retrospection
journal, December 2005


Applications of an amorphous silicon-based area detector for high-resolution, high-sensitivity and fast time-resolved pair distribution function measurements
journal, May 2007

  • Chupas, Peter J.; Chapman, Karena W.; Lee, Peter L.
  • Journal of Applied Crystallography, Vol. 40, Issue 3
  • DOI: 10.1107/S0021889807007856

Two-dimensional detector software: From real detector to idealised image or two-theta scan
journal, January 1996

  • Hammersley, A. P.; Svensson, S. O.; Hanfland, M.
  • High Pressure Research, Vol. 14, Issue 4-6, p. 235-248
  • DOI: 10.1080/08957959608201408

FIT2D : a multi-purpose data reduction, analysis and visualization program
journal, March 2016


Probing disorder in isometric pyrochlore and related complex oxides
journal, February 2016

  • Shamblin, Jacob; Feygenson, Mikhail; Neuefeind, Joerg
  • Nature Materials, Vol. 15, Issue 5
  • DOI: 10.1038/nmat4581

Instrumentation for fast in-situ X-ray structure measurements on non-equilibrium liquids
journal, December 2010

  • Weber, J. K. R.; Benmore, C. J.; Jennings, G.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 624, Issue 3
  • DOI: 10.1016/j.nima.2010.09.125

    Works referencing / citing this record:

    Phase transformations in oxides above 2000°C: experimental technique development
    journal, October 2018