First-principles prediction of disordering tendencies in pyrochlore oxides
- Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
Using first-principles calculations, we systematically predict the order-disorder energetics of series of zirconate (A{sub 2}Zr{sub 2}O{sub 7}), hafnate (A{sub 2}Hf{sub 2}O{sub 7}), titanate (A{sub 2}Ti{sub 2}O{sub 7}), and stannate (A{sub 2}Sn{sub 2}O{sub 7}) pyrochlores. The disordered defect-fluorite structure is modeled using an 88-atom two-sublattice special quasirandom structure (SQS) that closely reproduces the most relevant near-neighbor intrasublattice and intersublattice pair-correlation functions of the random mixture. The order-disorder transition temperatures of these pyrochlores estimated from our SQS calculations show overall good agreement with existing experiments. We confirm previous studies suggesting that the bonding in pyrochlores is not purely ionic and thus electronic effects also play a role in determining their disordering tendencies. Our results have important consequences for numerous applications, including nuclear waste forms and fast ion conductors.
- OSTI ID:
- 21192548
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 79, Issue 10; Other Information: DOI: 10.1103/PhysRevB.79.104203; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mn4+ emission in pyrochlore oxides
Probing disorder in isometric pyrochlore and related complex oxides
Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ATOMS
CHEMICAL BONDS
CORRELATION FUNCTIONS
CRYSTAL DEFECTS
DENSITY FUNCTIONAL METHOD
FORECASTING
HAFNATES
IONIC CONDUCTIVITY
MIXTURES
ORDER-DISORDER TRANSFORMATIONS
OXIDES
PYROCHLORE
RADIOACTIVE WASTE PROCESSING
STANNATES
TITANATES
TRANSITION TEMPERATURE
ZIRCONATES