Radiation Tolerance of Complex Oxides

Sickafus, Kurt E.; Minervini, Licia; Grimes, Robin W.; Valdez, James A.; Ishimaru, Manabu; Li, Fuxiang; McClellan, Kenneth J.; Hartmann, Thorsten

doi:10.1126/science.289.5480.748

Cited by 908 publications

(629 citation statements)

References 17 publications

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“…As described in a previous paper 7 , the energy calculated by DFT for complete disordering of the pyrochlore structure tends to increase as the B cation is changed from Zr to Hf to Ti to Sn, again consistent with empirical calculations which examined the smallest clusters of disordering defects (A B + B A + V O + O i ) 4 . In these clusters, the cation antisite pair were created as nearest neighbors.…”

Section: Resultssupporting

confidence: 49%

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Prediction of Irradiation Spectrum Effects in Pyrochlores

Uberuaga

Jiang

Stanek

et al. 2014

JOM

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The formation energy of cation antisites in pyrochlores (A2B2O7) has been correlated with the susceptibility to amorphize under irradation. Thus, density functional theory (DFT) calculations of antisite energetics can provide insights into the radiation tolerance of pyrochlores. Here, we show that the formation energy of antisite pairs in titanate pyrochlores, as opposed to other families of pyrochlores (A=Zr, Hf, or Sn), exhibit a strong dependence on the separation distance between the antisites. Classical molecular dynamics simulations of collision cascades in Er2Ti2O7 show that the average separation of antisite pairs is a function of the primary knock-on atom energy that creates the collision cascades. Together, these results suggest that the radiation tolerance of titanate pyrochlores may be sensitive to the irradiation conditions and might be controllable via the appropriate selection of ion beam parameters.

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Section: Resultssupporting

confidence: 49%

“…Past work has suggested a clear relationship between the propensity of complex oxides to disorder and their radiation tolerance 4,5 . This concept is formulated in the following defect reaction pair:…”

Section: Introductionmentioning

confidence: 99%

Prediction of Irradiation Spectrum Effects in Pyrochlores

Uberuaga

Jiang

Stanek

et al. 2014

JOM

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“…Pyrochlores and fluorites display a variety of interesting properties, such as oxide ion conductivity, radiation stability, gas sensitivity, catalytic activity, superconductivity and giant magnetoresistivity [1][2][3][4][5][6][7]. In particular their potential as oxide ion conductors has led to the investigations of the fluorite-pyrochlore structural boundary, with the aim of correlating the degree of anion disorder to conductivity [2,8].…”

Section: Introductionmentioning

confidence: 99%

From fluorite to pyrochlore: Characterisation of local and average structure of neodymium zirconate, Nd2Zr2O7

Payne

Tucker

Evans

2013

Journal of Solid State Chemistry

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NOTICE: this is the author's version of a work that was accepted for publication in Journal of solid state chemistry. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be re ected in this document. Changes may have been made to this work since it was submitted for publication. A de nitive version was subsequently published in Journal of solid state chemistry, 255, 2013, 10.1016/j.jssc.2013.07.001 Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThe structural characterisation of Nd 2 Zr 2 O 7 prepared via a precursor route was performed using a combination of local and average structure probes (neutron total scattering, X-ray and neutron diffraction). We present the first total scattering and reverse Monte Carlo (RMC) modelling study of Nd 2 Zr 2 O 7 , which provides compelling evidence for the adoption of a disordered fluorite-type structure by Nd 2 Zr 2 O 7 prepared by a low-temperature precursor route.Annealing the material at high temperatures leads to a transformation to a pyrochlore-type structure; however, Rietveld refinement using powder neutron diffraction data shows that the oxygen sublattice retains a degree of disorder.

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“…Due to its radiation tolerance, pyrochlores are seen as a candidate for application such as inert matrix fuels, nuclear waste immobilization and geological age-dating. [1,2] However, radiation under such extreme conditions introduces phase transformation in the ordered pyrochlore structure, which is critical to understand for such applications. High energy ion irradiation (MeV to GeV) on pyrochlores is seen as an important experiment to understand the phase transformations which take place due to localized (nanoscale) energy transfer to the lattice in extremely short time period (~ns).…”

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Short-Range Atomic Ordering in Amorphous Ion-Tracks in Pyrochlores

et al. 2015

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Pyrochlore structured complex oxides (A 2 B 2 O 7 ) have attracted attention due to its unique physical, chemical and electrical properties. Due to its radiation tolerance, pyrochlores are seen as a candidate for application such as inert matrix fuels, nuclear waste immobilization and geological age-dating.[1,2] However, radiation under such extreme conditions introduces phase transformation in the ordered pyrochlore structure, which is critical to understand for such applications. High energy ion irradiation (MeV to GeV) on pyrochlores is seen as an important experiment to understand the phase transformations which take place due to localized (nanoscale) energy transfer to the lattice in extremely short time period (~ns). [3] In the present work, Gd 2 Ti 2 O 7 is irradiated with high energy ions to form nanoscale amorphous tracks along the ion penetration path. It has been previously reported that a concentric shell of disordered crystalline phase of defect fluorite is formed around the amorphous ion track in Gd 2 Zr x Ti (1-x) O 7 pyrochlores.[4] In the case of Gd 2 Ti 2 O 7 , there are studies reporting similar formation of a concentric defect-fluorite phase. However, atomic scale characterization and its effect on electronic structure of material has not yet been understood which is important for performance of such materials. Here, we report the detailed study of concentric defect fluorite phase existing around amorphous ion track by using high-angle annular dark field (HAADF) imaging and electron energy-loss spectroscopy (EELS) in an aberration corrected scanning transmission electron microscope (STEM).Here, a (HAADF) image of an ion track in Gd 2 Ti 2 O 7 pyrochlore lattice oriented in [110] zone axis is shown in Fig. 1(a). The ion track was created by 2.2 GeV Au ion irradiation. The image analysis based on the atomic column contrast reveals that a distinct crystalline phase with thickness of 2-3 atomic planes (0.5-1 nm) forms at the periphery of the ion track. This phase is identified as defect fluorite phase which is a disordered crystalline derivative of the ordered pyrochlore phase. The contrast variation seen in amorphous region is due to tilting of ion track from perfect normal view. To understand the electronic structure, electron energy-loss spectroscopy (EELS) is performed. Fig. 1(b) and (c) show the Ti L-edge (456 eV) and O K-edge (532 eV) respectively from ordered crystalline and amorphous region. In an important observation, the Ti L-edge in the amorphous ion track features crystal field splitting similar to the one from crystalline region. This result indicates the presence of short-range ordering in the Ti-O octahedra in amorphous phase of Gd 2 Ti 2 O 7 . In addition to that, the shift in the e g and t 2g peaks in both L 3 and L 2 shows the evidence of Ti-O octahedral distortion in the amorphous phase. Fig. 1(c) shows that the pre-peak merges with the main peak and results in a significant

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Radiation Tolerance of Complex Oxides

Cited by 908 publications

References 17 publications

Prediction of Irradiation Spectrum Effects in Pyrochlores

Prediction of Irradiation Spectrum Effects in Pyrochlores

From fluorite to pyrochlore: Characterisation of local and average structure of neodymium zirconate, Nd2Zr2O7

Short-Range Atomic Ordering in Amorphous Ion-Tracks in Pyrochlores

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