Self-diffusion is a fundamental physical process that, in solid materials, is intimately correlated with both microstructure and functional properties. In this work, a universal approach is presented to precisely characterize self-diffusion in ionic solids by isotopically enriching anions and/or cations at specific locations within an epitaxial film stack, and characterize their redistribution at high spatial resolution with atom probe tomography. Nanoscale anion diffusivity is quantified in epitaxial α-Fe2O3 thin films deposited by molecular beam epitaxy with a thin (10 nm) buried layer highly enriched in 18O. The isotopic sensitivity of the atom probe allows precise measurement of 18O distribution across the sharp interfaces between this layer and the surrounding Fe2O3 after annealing. Short-circuit anion diffusion through 1D and 2D structural defects in Fe2O3 are also directly visualized in 3D. This versatile approach to study precisely tailored thin film samples at high spatial and mass fidelity will facilitate a deeper understanding of atomic-scale diffusion phenomena.
Kaspar, Tiffany C., et al. "Bulk and Short-Circuit Anion Diffusion in Epitaxial Fe<sub>2</sub>O<sub>3</sub> Films Quantified Using Buried Isotopic Tracer Layers." Advanced Materials Interfaces, vol. 8, no. 9, Mar. 2021. https://doi.org/10.1002/admi.202001768
@article{osti_1783601,
author = {Kaspar, Tiffany C. and Taylor, Sandra D. and Yano, Kayla H. and Lach, Timothy G. and Zhou, Yadong and Zhu, Zihua and Kohnert, Aaron Anthony and Still, Evan K. and Hosemann, Peter and Spurgeon, Steven R. and others},
title = {Bulk and Short-Circuit Anion Diffusion in Epitaxial Fe<sub>2</sub>O<sub>3</sub> Films Quantified Using Buried Isotopic Tracer Layers},
annote = {Self-diffusion is a fundamental physical process that, in solid materials, is intimately correlated with both microstructure and functional properties. In this work, a universal approach is presented to precisely characterize self-diffusion in ionic solids by isotopically enriching anions and/or cations at specific locations within an epitaxial film stack, and characterize their redistribution at high spatial resolution with atom probe tomography. Nanoscale anion diffusivity is quantified in epitaxial α-Fe2O3 thin films deposited by molecular beam epitaxy with a thin (10 nm) buried layer highly enriched in 18O. The isotopic sensitivity of the atom probe allows precise measurement of 18O distribution across the sharp interfaces between this layer and the surrounding Fe2O3 after annealing. Short-circuit anion diffusion through 1D and 2D structural defects in Fe2O3 are also directly visualized in 3D. This versatile approach to study precisely tailored thin film samples at high spatial and mass fidelity will facilitate a deeper understanding of atomic-scale diffusion phenomena.},
doi = {10.1002/admi.202001768},
url = {https://www.osti.gov/biblio/1783601},
journal = {Advanced Materials Interfaces},
issn = {ISSN 2196-7350},
number = {9},
volume = {8},
place = {United States},
publisher = {Wiley-VCH},
year = {2021},
month = {03}}