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∑3 Twin Boundaries in Gd2Ti2O7 Pyrochlore: Pathways for Oxygen Migration
Ashish Kumar Gupta1, Gaurav Arora2, Dilpuneet S Aidhy2
1School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, United States.
Investigating twin boundaries in Gd2Ti2O7 pyrochlores reveals atomic distortions and a 25% lower oxygen migration barrier at these defects, facilitating faster oxygen transport and property manipulation.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Crystallography
Background:
- Twin boundaries (TBs) are common atomic imperfections in complex oxides, influencing material properties.
- Understanding TB chemistry is crucial for manipulating functional properties, especially in pyrochlores.
Purpose of the Study:
- To provide atomic-scale insights into a specific twin boundary (∑3(111̅)⟨11̅0⟩) in pyrochlore-structured Gd2Ti2O7.
- To investigate the impact of the TB on atomic structure and oxygen migration.
Main Methods:
- Atomic-resolution electron microscopy for structural analysis.
- Atomistic modeling to calculate oxygen migration barriers.
Main Results:
- Observed atomic distortions and increased Gd-Gd and Ti-Ti bond lengths at the TB.
- Calculated a ~25% lower oxygen migration barrier (0.9 eV vs. 1.23 eV) at the TB compared to the bulk.
Conclusions:
- The study elucidates the atomic arrangement at twin boundaries in pyrochlores.
- Lowered oxygen migration barriers at TBs suggest enhanced oxygen transport, enabling defect-property control.
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