Defect Distributions and Transport in Nanocomposites: A Theoretical Perspective

Uberuaga, Blas P.; Martínez, Enrique Mínguez; Bi, Zhenxing; Zhuo, Mujin; Jia, Q. X.; Nastasi, M.; Misra, Amit; Caro, A.

doi:10.1080/21663831.2013.805442

Cited by 21 publications

(23 citation statements)

References 29 publications

(31 reference statements)

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“…In a recent paper [12], we examined how the defect content near a heterophase interface depends on the relative thermodynamic and kinetic properties of defects within 40 the two phases. A one-dimensional model that qualitatively reproduced the observations from a series of experiments [7][8][9][10] showed that significant changes in the defect accumulation near the interface could occur even though the interface itself did not trap defects.…”

Section: Introductionmentioning

confidence: 99%

Ideal sinks are not always ideal: Radiation damage accumulation in nanocomposites

Uberuaga

Choudhury

Caro

2015

Journal of Nuclear Materials

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Designing radiation tolerant materials is one of the primary challenges associated with advanced nuclear energy systems. One attractive route that has received much attention worldwide is to introduce a high density of sinks, often in the form of interfaces or secondary phases. Here, we develop a simple model of such nanocomposites and examine the ramifications of various factors on the overall radiation stability of the material. In particular, we determine how the distribution of secondary phases, the relative sink strength of those phases, and the irradiation temperature influence the radiation tolerance of the matrix. We find that the best scenario is one in which the sinks have intermediate strength, transiently trapping defects before releasing them back into the matrix. Neither perfect sinks nor the complete absence of sinks perform as well. This provides new insight into the optimal properties of nanocomposites for radiation damage environments.

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Section: Introductionmentioning

confidence: 99%

Ideal sinks are not always ideal: Radiation damage accumulation in nanocomposites

Uberuaga

Choudhury

Caro

2015

Journal of Nuclear Materials

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“…T he last decade has witnessed unabated growth of research on oxide materials due to their wide-ranging applications that include information storage [1][2][3] , radiation-tolerant materials 4,5 , fuel cells 6,7 and batteries 8 . In the majority of these applications, vital properties of nanocomposite oxides are influenced or even controlled by oxide interfaces.…”

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confidence: 99%

Termination chemistry-driven dislocation structure at SrTiO3/MgO heterointerfaces

et al. 2014

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Exploiting the promise of nanocomposite oxides necessitates a detailed understanding of the dislocation structure at the interfaces, which governs diverse and technologically relevant properties. Here we report atomistic simulations demonstrating a strong dependence of the dislocation structure on the termination chemistry at the SrTiO 3 /MgO heterointerface. The SrO-and TiO 2 -terminated interfaces exhibit distinct nearest neighbour arrangements between cations and anions, leading to variations in local electrostatic interactions across the interface that ultimately dictate the dislocation structure. Networks of dislocations with different Burgers vectors and dislocation spacing characterize the two interfaces. These networks in turn influence the overall stability of and the behaviour of oxygen vacancies at the heterointerface, which will dictate vital properties such as mass transport at the interface. To date, the observed correlation between the dislocation structure and the termination chemistry at the interface has not been recognized, and offers novel avenues for fine-tuning oxide nanocomposites with enhanced functionalities.

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“…Thus, as one might expect, in more complicated nanocomposites in which the interfacial structure leads to enhanced interactions with defects, the overall response of the material will be a combination of both the defect properties within each phase 34 as well as how those defects interact with the interfaces. 34 Our results suggest that even if the steps could act as sinks for radiationinduced defects, other mechanisms discussed above, such as antisite formation, will dictate the final behavior of the material, and in the present case could be accountable for the amorphization observed in the vicinity of steps. 37 Finally, our results have ramifications beyond radiation damage evolution.…”

Section: Implications To Radiation Damagementioning

confidence: 50%

“…28 More recently, efforts combining experiment and theory have focused on elucidating the microstructure evolution after irradiation of model ceramic-ceramic thin film composites. 21,22,26,34 This work revealed that coherent interfaces could play a key role in microstructure evolution after irradiation even while not operating as a thermodynamic sink for radiation-induced defects. Complex behavior, in the form of the emergence of both a defect denuded zone (enhanced tolerance) and interfacial amorphization (degraded tolerance) at the same TiO 2 /STO interface, was observed.…”

Section: Introductionmentioning

confidence: 84%

Defect interactions with stepped CeO2/SrTiO3 interfaces: Implications for radiation damage evolution and fast ion conduction

Dholabhai

Aguiar

Misra

et al. 2014

The Journal of Chemical Physics

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Due to reduced dimensions and increased interfacial content, nanocomposite oxides offer improved functionalities in a wide variety of advanced technological applications, including their potential use as radiation tolerant materials. To better understand the role of interface structures in influencing the radiation damage tolerance of oxides, we have conducted atomistic calculations to elucidate the behavior of radiation-induced point defects (vacancies and interstitials) at interface steps in a model CeO2/SrTiO3 system. We find that atomic-scale steps at the interface have substantial influence on the defect behavior, which ultimately dictate the material performance in hostile irradiation environments. Distinctive steps react dissimilarly to cation and anion defects, effectively becoming biased sinks for different types of defects. Steps also attract cation interstitials, leaving behind an excess of immobile vacancies. Further, defects introduce significant structural and chemical distortions primarily at the steps. These two factors are plausible origins for the enhanced amorphization at steps seen in our recent experiments. The present work indicates that comprehensive examination of the interaction of radiation-induced point defects with the atomic-scale topology and defect structure of heterointerfaces is essential to evaluate the radiation tolerance of nanocomposites. Finally, our results have implications for other applications, such as fast ion conduction.

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Defect Distributions and Transport in Nanocomposites: A Theoretical Perspective

Cited by 21 publications

References 29 publications

Ideal sinks are not always ideal: Radiation damage accumulation in nanocomposites

Ideal sinks are not always ideal: Radiation damage accumulation in nanocomposites

Termination chemistry-driven dislocation structure at SrTiO3/MgO heterointerfaces

Defect interactions with stepped CeO2/SrTiO3 interfaces: Implications for radiation damage evolution and fast ion conduction

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