The impact of chemistry on anion migration in bixbyite-structured lanthanide oxides

Uberuaga, Blas Pedro [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000169346219); Chattopadhyay, Soham [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)]

doi:10.1016/j.ssi.2026.117264

DOE OSTI · 3391251

The impact of chemistry on anion migration in bixbyite-structured lanthanide oxides

Uberuaga, Blas Pedro [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000169346219)·Chattopadhyay, Soham [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)]

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Abstract

This manuscript describes atomistic calculations of oxygen vacancy and interstitial migration in bixbyite structured lanthanide oxides. We examine two types of compounds, one in which only one type of lanthanide cation is present and a second class in which two lanthanides are present in a 3:1 ratio as dictated by the symmetry of the bixbyite crystal structure. Using temperature accelerated dynamics and the nudged elastic band method, we quantify the role of chemistry on the energy barriers for the most important pathways for both vacancy and interstitial migration. We then analyze the impact of these variations on the overall diffusivity of each defect, quantifying the contribution of each pathway using the theory of kinosons. We find that vacancy mobility can vary by as much as three orders of magnitude through changes in chemistry at 500 K. Changes in interstitial mobility are more modest but can still vary by an order of magnitude. This points to the ability to tune the mass transport characteristics of these compounds through appropriate choices in chemistry. We have also included supplementary information containing the atomic structures of the relevant pathways.

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Uberuaga, Blas Pedro [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)] (ORCID:0000000169346219), Chattopadhyay, Soham [Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)]. 2026-10-01. The impact of chemistry on anion migration in bixbyite-structured lanthanide oxides. https://doi.org/10.1016/j.ssi.2026.117264

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