The mechanism of grain growth at general grain boundaries in SrTiO3

Sternlicht, Hadas; Rheinheimer, Wolfgang; Mehlmann, A.; Rothschild, Avner; Hoffmann, Michael J.; Kaplan, Wayne D.

doi:10.1016/j.scriptamat.2020.07.015

Cited by 15 publications

(9 citation statements)

References 49 publications

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“…[80] Despite intense TEM investigation, no difference of the grain-boundary structure could be found for these two types. [53][54][55][56] However, there seem to be chemical changes: in bimodal microstructures, grain boundaries of small grains tend to be Ti rich, while large grains tend to have stoichiometric boundaries or even Sr excess. [87,88] It must be pointed out that these TEM observations are a trend only due to low statistics.…”

Section: Field-assisted Grain-boundary Transitionsmentioning

confidence: 99%

“…[6][7][8] Strontium titanate was chosen as a model system because of its well-known fundamental physics, including the defect chemistry, [34] defect migration, [13,[35][36][37][38][39][40] space-charge layers, [41][42][43][44] field-free grain growth data, [45][46][47][48][49][50][51][52] and the atomistic grain growth mechanism. [53][54][55][56] We use the same current-blocking setup as in previous studies (refs. [6,7], Figure 1) to shed light on the influence of atmosphere, alternating electric fields and single-crystal orientation on grain growth and densification during field-assisted heat treatments of strontium titanate.…”

Section: Introductionmentioning

confidence: 99%

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Impact of AC and DC Electric Fields on the Microstructure Evolution in Strontium Titanate

2023

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Herein, the impact of AC and DC electric fields on microstructure evolution in strontium titanate is investigated. The focus is on nonthermal effects by using current‐blocking electrodes. The seeded polycrystal technique allows investigating the impact of a DC electric field on grain growth for different grain‐boundary orientations and the impact of the surrounding atmosphere. As in previous studies, faster grain growth is observed at the negative electrode. This effect is stronger for the (100) orientation and in reducing atmosphere. In AC electric field at 1450 °C, a low‐enough frequency results in faster grain growth at both electrodes. These findings agree well with previous studies, where an electromigration of oxygen vacancies is found to cause a local reduction at the negative electrode, resulting in less space charge, less cationic segregation, and a higher grain‐boundary mobility. At 1500 °C, AC electric fields are found to cause a complete grain growth stagnation at very small grain sizes. This behavior is unexpected; the physical reasons are not clear. Herein, a brief study of sintering in DC electric field reveals slightly faster sintering if a field is applied.

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Section: Field-assisted Grain-boundary Transitionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impact of AC and DC Electric Fields on the Microstructure Evolution in Strontium Titanate

2023

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“…Discontinuous GB motion is often observed in in situ TEM studies. GBs jump (53,58,62), reverse direction (57,58,62), bulge (57), restructure (61), and oscillate between positions (64,65). Often these movements are attributed to triggering events (58) that involve other vicinal defects such as stacking faults (59), twins (58), TJs (53,62), and free surfaces (53,62,65).…”

Section: Microscopic Observations Of Grain Boundary Migrationmentioning

confidence: 99%

Grain Boundary Migration in Polycrystals

Rohrer

Chesser

Krause

et al. 2023

Annu. Rev. Mater. Res.

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Grain boundaries in polycrystalline materials migrate to reduce the total excess energy. It has recently been found that the factors governing migration rates of boundaries in bicrystals are insufficient to explain boundary migration in polycrystals. We first review our current understanding of the atomistic mechanisms of grain boundary migration based on simulations and high-resolution transmission electron microscopy observations. We then review our current understanding at the continuum scale based on simulations and observations using high-energy diffraction microscopy. We conclude that detailed comparisons of experimental observations with atomistic simulations of migration in polycrystals (rather than bicrystals) are required to better understand the mechanisms of grain boundary migration, that the driving force for grain boundary migration in polycrystals must include factors other than curvature, and that current simulations of grain growth are insufficient for reproducing experimental observations, possibly because of an inadequate representation of the driving force. Expected final online publication date for the Annual Review of Materials Research, Volume 53 is July 2023. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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“…Atomic and nanoscale imaging by HRTEM is a common approach to assess GBs in many oxide systems, such as alumina [197][198][199][200], zirconia [74,201,202], spinel [203,204], ceria [76,205], etc. [206][207][208] In addition, aberration-corrected TEM is widely used in oxides [27,[209][210][211]. HRTEM micrographs and schematic models of GBs in a rare-earth (RE) doped alumina and a pure alumina are shown in Figure 24 [195].…”

Section: Imaging Atomic and Nano Structuresmentioning

confidence: 99%

A Review of Grain Boundary and Heterointerface Characterization in Polycrystalline Oxides by (Scanning) Transmission Electron Microscopy

et al. 2021

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Interfaces such as grain boundaries (GBs) and heterointerfaces (HIs) are known to play a crucial role in structure-property relationships of polycrystalline materials. While several methods have been used to characterize such interfaces, advanced transmission electron microscopy (TEM) and scanning TEM (STEM) techniques have proven to be uniquely powerful tools, enabling quantification of atomic structure, electronic structure, chemistry, order/disorder, and point defect distributions below the atomic scale. This review focuses on recent progress in characterization of polycrystalline oxide interfaces using S/TEM techniques including imaging, analytical spectroscopies such as energy dispersive X-ray spectroscopy (EDXS) and electron energy-loss spectroscopy (EELS) and scanning diffraction methods such as precession electron nano diffraction (PEND) and 4D-STEM. First, a brief introduction to interfaces, GBs, HIs, and relevant techniques is given. Then, experimental studies which directly correlate GB/HI S/TEM characterization with measured properties of polycrystalline oxides are presented to both strengthen our understanding of these interfaces, and to demonstrate the instrumental capabilities available in the S/TEM. Finally, existing challenges and future development opportunities are discussed. In summary, this article is prepared as a guide for scientists and engineers interested in learning about, and/or using advanced S/TEM techniques to characterize interfaces in polycrystalline materials, particularly ceramic oxides.

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The mechanism of grain growth at general grain boundaries in SrTiO3

Cited by 15 publications

References 49 publications

Impact of AC and DC Electric Fields on the Microstructure Evolution in Strontium Titanate

Impact of AC and DC Electric Fields on the Microstructure Evolution in Strontium Titanate

Grain Boundary Migration in Polycrystals

A Review of Grain Boundary and Heterointerface Characterization in Polycrystalline Oxides by (Scanning) Transmission Electron Microscopy

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