Insights into the Radiation Response of Pyrochlores from Calculations of Threshold Displacement Events

Journal Article · Sat Oct 15 00:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2120889· OSTI ID:859981

Devanathan, Ram; Weber, William J

We have used molecular dynamics simulations to examine the displacement threshold energy (Ed) surface for cations and anions in Gd2Ti2O7 and Gd2Zr2O7 pyrochlores. In both pyrochlores, the Ed surface is highly anisotropic and it requires less energy to displace anions than cations. Both anion and cation Ed values are higher in the titanate compared to the zirconate. Titanium displacement energies are in excess of 170 eV for all directions examined, because cation exchange is less energetically favorable in Gd2Ti2O7 compared to Gd2Zr2O7. These high energy Ti displacements result in the formation of defect clusters that may prevent efficient defect recovery. This provides an explanation for the difference in susceptibility to amorphization between titanate and zirconate pyrochlores.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 859981
• Report Number(s): PNNL-SA-45842; JAPIAU; 8208; KC0201020; TRN: US0504802
• Journal Information: Journal of Applied Physics, Vol. 98, Issue 8; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CRYSTAL DEFECTS
RADIATION EFFECTS
THRESHOLD ENERGY
TITANIUM OXIDES
ZIRCONIUM OXIDES
PYROCHLORE
RADIOACTIVE WASTE DISPOSAL
GADOLINIUM OXIDES
ATOMIC DISPLACEMENTS
environmental molecular sciences laboratory
pyrochlore
displacement energy
molecular dynamics
nuclear waste disposal