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This content will become publicly available on December 1, 2026

Title: Structural effects on oxygen vacancies and redox behavior in Mn-based perovskite oxides
A series of perovskite oxides (Ln = La, Pr, Nd, Gd; A = Ba, Sr) was investigated to understand the effects of A-site cation size on oxygen vacancy formation. Quasirandom mixed structures were generated using Alloy Theoretic Automated Toolkit (ATAT), followed by density functional theory (DFT) calculations. While mixing the orthorhombic structures with the hexagonal AMnO3 structures leads to lattices and global symmetries closer to cubic, the average volume generally increases with the average ionic size, and the local bond and angles exhibit more variations due to A-site mixing. DFT calculations and a statistical model were combined to predict oxygen reduction abilities. Thermogravimetric analysis (TGA) provided experimental validation of these predictions by measuring changes in oxygen non-stoichiometry under controlled conditions. Both indicated that larger A-site ionic size differences lead to greater, consistent with the larger variation in local structures, and enhanced redox capabilities. This combined computational-experimental approach highlights the importance of local structure variation, instead of average properties, in A-site cation engineering to optimize perovskite oxides for different devices relying on oxygen vacancy redox activity.  more » « less
Award ID(s):
2328044
PAR ID:
10652519
Author(s) / Creator(s):
; ; ; ; ; ;
Publisher / Repository:
Solid State Ionics
Date Published:
Journal Name:
Solid State Ionics
Volume:
432
Issue:
C
ISSN:
0167-2738
Page Range / eLocation ID:
117067
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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