Pressure induced structural transformation in Gd2Ti2O7 and Gd2Zr2O7

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Journal of Physics: Condensed Matter

DOI:https://doi.org/10.1088/0953-8984/23/3/035501· OSTI ID:1003764

Xiao, Haiyan ^[1]; Weber, William J ^[2]

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1. Pacific Northwest National Laboratory (PNNL)
2. ORNL

Ab initio total energy calculations have been performed to study the phase stability of Gd2Ti2O7 and Gd2Zr2O7 pyrochlores over the pressure range from 0 to 60 GPa. Both compounds are unstable under pressure, and phase transformations to the defect-cotunnite structure are predicted. The phase transformation pressure of 43.6 GPa for Gd2Ti2O7 is considerably larger than the value of 13 GPa for Gd2Zr2O7, in good agreement with experiments. The decreased structural stability of Gd2Zr2O7 under pressure, relative to Gd2Ti2O7, is a consequence of the lower compressibility of the Zr O bond and the higher compressibility of the Gd O bond. In addition, the Gd 4f electrons are found to have only a small effect in determining the pressure induced phase transformation.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1003764
• Journal Information: Journal of Physics: Condensed Matter, Journal Name: Journal of Physics: Condensed Matter Journal Issue: 3 Vol. 23; ISSN 0953-8984; ISSN 1361-648X
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COMPRESSIBILITY
ELECTRONS
High pressure
PHASE STABILITY
PHASE TRANSFORMATIONS
PRESSURE RANGE
Phase transformations
Pyrochlores
STABILITY
TRANSFORMATIONS