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Title: High-pressure behavior of A 2 B 2 O 7 pyrochlore (A=Eu, Dy; B=Ti, Zr)

Journal Article · · Journal of Applied Physics
DOI: https://doi.org/10.1063/1.4974871 · OSTI ID:1360963
ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [2];  [3];  [1];  [4]
  1. Stanford Univ., CA (United States). Dept. of Geological Sciences
  2. National Polytechnic Institute Saltillo Unit, Coahuila (Mexico)
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source
  4. Stanford Univ., CA (United States). Dept. of Geological Sciences; SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Inst. for Materials and Energy Sciences

In situ high-pressure X-ray diffraction and Raman spectroscopy were used to determine the influence of composition on the high-pressure behavior of A2B2O7 pyrochlore (A = Eu, Dy; B = Ti, Zr) up to ~50 GPa. Based on X-ray diffraction results, all compositions transformed to the high-pressure cotunnite structure. The B-site cation species had a larger effect on the transition pressure than the A-site cation species, with the onset of the phase transformation occurring at ~41 GPa for B = Ti and ~16 GPa B = Zr. However, the A-site cation affected the kinetics of the phase transformation, with the transformation for compositions with the smaller ionic radii, i.e., A = Dy, proceeding faster than those with a larger ionic radii, i.e., A = Eu. These results were consistent with previous work in which the radius-ratio of the A- and B-site cations determined the energetics of disordering, and compositions with more similarly sized A- and B-site cations had a lower defect formation energy. Raman spectra revealed differences in the degree of short-range order of the different compositions. Due to the large phase fraction of cotunnite at high pressure for B = Zr compositions, Raman modes for cotunnite could be observed, with more modes recorded for A = Eu than A = Dy. These additional modes are attributed to increased short-to-medium range ordering in the initially pyrochlore structured Eu2Zr2O7 as compared with the initially defect-fluorite structured Dy2Zr2O7.

Research Organization:
SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Energy Frontier Research Centers (EFRC) (United States). Materials Science of Actinides (MSA); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC02-76SF00515; SC0001089; NA0001974; FG02-99ER45775; AC02-06CH11357; AC02-05CH11231
OSTI ID:
1360963
Alternate ID(s):
OSTI ID: 1361754; OSTI ID: 1468338
Journal Information:
Journal of Applied Physics, Vol. 121, Issue 4; ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 35 works
Citation information provided by
Web of Science

References (44)

Connection between oxygen-ion conductivity of pyrochlore fuel-cell materials and structural change with composition and temperature journal April 2000
Raman and x-ray absorption spectroscopy study of the phase evolution induced by mechanical milling and thermal treatments in R 2 Ti 2 O 7 pyrochlores journal September 2011
Oxygen migration in A2B2O7 pyrochlores journal April 2001
Quantum and thermal spin relaxation in the diluted spin ice Dy 2 − x M x Ti 2 O 7 ( M = Lu , Y ) journal November 2004
Structural distortions and phase transformations in Sm2Zr2O7 pyrochlore at high pressures journal June 2007
High-pressure x-ray diffraction study of CeO 2 to 70 GPa and pressure-induced phase transformation from the fluorite structure journal October 1988
Disorder in Pyrochlore Oxides journal August 2000
Phonon spectrum, thermodynamic properties, and pressure-temperature phase diagram of uranium dioxide journal September 2013
High pressure phase transitions and compressibilities of Er[sub 2]Zr[sub 2]O[sub 7] and Ho[sub 2]Zr[sub 2]O[sub 7] journal January 2008
Silicone fluid as a high‐pressure medium in diamond anvil cells journal February 1996
Nanoscale manipulation of the properties of solids at high pressure with relativistic heavy ions journal September 2009
Behavior of actinide dioxides under pressure:  U O 2 and Th O 2 journal July 2004
Dirac Strings and Magnetic Monopoles in the Spin Ice Dy2Ti2O7 journal September 2009
Rare-earth titanates and stannates of pyrochlore structure; vibrational spectra and force fields journal April 1983
Influence of structural disorder on the dynamics of mobile oxygen ions in Dy2(Ti1−yZry)2O7 journal November 2007
High-pressure Raman and x-ray study of the spin-frustrated pyrochlore Gd 2 Ti 2 O 7 journal August 2006
Systematics of the pyrochlore structure type, ideal A2B2X6Y journal June 1984
Phase Stability and Pressure Dependence of Defect Formation in Gd 2 Ti 2 O 7 and Gd 2 Zr 2 O 7 Pyrochlores journal January 2008
Defect formation energies in A 2 B 2 O 7 pyrochlores journal October 2015
The Structural Transformation from the Pyrochlore Structure, A2B2O7, to the Fluorite Structure, AO2, Studied by Raman Spectroscopy and Defect Chemistry Modeling journal August 2001
Pressure-induced order–disorder transitions in pyrochlore RE2Ti2O7 (RE=Y, Gd) journal September 2006
Zirconate pyrochlores under high pressure journal January 2010
Characterization of Anion Disorder in Zirconate A 2 B 2 O 7 Compounds by Raman Spectroscopy journal September 1979
Structural changes and pressure-induced amorphization in rare earth titanates RE2Ti2O7 (RE: Gd, Sm) with pyrochlore structure journal September 2005
Hydrostatic limits of 11 pressure transmitting media journal March 2009
Cooperative oxygen ion dynamics in Gd 2 Ti 2 − y Zr y O 7 journal April 2005
Atomic disorder in Gd 2 Zr 2 O 7 pyrochlore journal May 2015
Oxide pyrochlores — A review journal January 1983
Pressure and temperature phase diagram of Gd 2 Ti 2 O 7 under irradiation journal November 2014
High-pressure structural changes in the Gd 2 Zr 2 O 7 pyrochlore journal December 2007
Radiation-induced amorphization of rare-earth titanate pyrochlores journal October 2003
DIOPTAS : a program for reduction of two-dimensional X-ray diffraction data and data exploration journal May 2015
Ab initio investigation of phase stability of Y 2 Ti 2 O 7 and Y 2 Zr 2 O 7 under high pressure journal December 2009
Radiation Tolerance of Complex Oxides journal August 2000
Preparation, XRD and Raman spectroscopic studies on new compounds RE2Hf2O7 (RE=Dy, Ho, Er, Tm, Lu, Y): Pyrochlores or defect-fluorite? journal July 2006
Order–disorder transition in the Nd2−yYyZr2O7 system: Probed by X-ray diffraction and Raman spectroscopy journal January 2010
Nuclear waste disposal—pyrochlore (A2B2O7): Nuclear waste form for the immobilization of plutonium and “minor” actinides journal June 2004
Calibration of the ruby pressure gauge to 800 kbar under quasi-hydrostatic conditions journal January 1986
Synthesis of disordered pyrochlores, Ti2O7 (, Gd and Dy), by mechanical milling of constituent oxides journal April 2005
Pressure-Induced Disordering and Anomalous Lattice Expansion in La 2 Zr 2 O 7 Pyrochlore journal June 2010
Pressure induced structural transformation in Gd 2 Ti 2 O 7 and Gd 2 Zr 2 O 7 journal January 2011
High ionic conductivity in the pyrochlore-type Gd2−yLayZr2O7 solid solution (0≤y≤1) journal November 2008
Probing disorder in isometric pyrochlore and related complex oxides journal February 2016
High-pressure Raman study of CeO 2 to 35 GPa and pressure-induced phase transformation from the fluorite structure journal March 1988

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Pressure-induced order–disorder transition in Gd 1.5 Ce 0.5 Ti 2 O 7 pyrochlore journal September 2019
Pressure-Tuned Interactions in Frustrated Magnets: Pathway to Quantum Spin Liquids? journal December 2019
Strain engineered pyrochlore at high pressure journal May 2017
Pressure-induced order–disorder transition in Gd 1.5 Ce 0.5 Ti 2 O 7 pyrochlore journal September 2019