skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Visualizing oxygen anion transport pathways in NdBaCo 2O 5+δ by in situ neutron diffraction

Abstract

We characterized the layered perovskite NdBaCo 2O 5+δ (NBCO) using neutron powder diffraction under in situ conditions from 577–852 °C and in 10 -1 to 10 -4 atm oxygen. The best fit to the data was obtained in the tetragonal (P4/mmm) space group. No oxygen atom vacancy ordering was observed that warranted a lowering of the symmetry to orthorhombic (Pmmm). Two P4/mmm structural models were investigated: Model 1 (no split sites) and Model 2 (split Nd and O 2 sites). Furthermore, transport of oxygen through the material via the vacancy hopping mechanism will likely involve the nearest-neighbor oxygen atom sites in the Nd layer. Total oxygen stoichiometry values were in the range 5.51 ≤ δ ≤ 5.11. The tetragonal lattice parameters increased with temperature as expected. But, the a-axis expands while the c-axis contracts with decreasing pO 2 at a given temperature due to increasing vacancy concentration in the Nd layer.

Authors:
 [1];  [2];  [2];  [2];  [3];  [3];  [3];  [4]
  1. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Chemical Engineering
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source
  3. Univ. of Houston, TX (United States). Dept. of Chemistry
  4. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Chemical Engineering; Lehigh Univ., Bethlehem, PA (United States). Dept. of Chemical Engineering
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1143576
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Journal of Materials Chemistry. A
Additional Journal Information:
Journal Volume: 1; Journal Issue: 9; Journal ID: ISSN 2050-7488
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Cox-Galhotra, Rosemary A., Huq, Ashfia, Hodges, Jason P., Kim, Jung-Hyun, Yu, Chengfei, Wang, Xiqu, Jacobson, Allan J., and McIntosh, Steven. Visualizing oxygen anion transport pathways in NdBaCo2O5+δ by in situ neutron diffraction. United States: N. p., 2013. Web. doi:10.1039/c3ta01308a.
Cox-Galhotra, Rosemary A., Huq, Ashfia, Hodges, Jason P., Kim, Jung-Hyun, Yu, Chengfei, Wang, Xiqu, Jacobson, Allan J., & McIntosh, Steven. Visualizing oxygen anion transport pathways in NdBaCo2O5+δ by in situ neutron diffraction. United States. https://doi.org/10.1039/c3ta01308a
Cox-Galhotra, Rosemary A., Huq, Ashfia, Hodges, Jason P., Kim, Jung-Hyun, Yu, Chengfei, Wang, Xiqu, Jacobson, Allan J., and McIntosh, Steven. Mon . "Visualizing oxygen anion transport pathways in NdBaCo2O5+δ by in situ neutron diffraction". United States. https://doi.org/10.1039/c3ta01308a.
@article{osti_1143576,
title = {Visualizing oxygen anion transport pathways in NdBaCo2O5+δ by in situ neutron diffraction},
author = {Cox-Galhotra, Rosemary A. and Huq, Ashfia and Hodges, Jason P. and Kim, Jung-Hyun and Yu, Chengfei and Wang, Xiqu and Jacobson, Allan J. and McIntosh, Steven},
abstractNote = {We characterized the layered perovskite NdBaCo2O5+δ (NBCO) using neutron powder diffraction under in situ conditions from 577–852 °C and in 10-1 to 10-4 atm oxygen. The best fit to the data was obtained in the tetragonal (P4/mmm) space group. No oxygen atom vacancy ordering was observed that warranted a lowering of the symmetry to orthorhombic (Pmmm). Two P4/mmm structural models were investigated: Model 1 (no split sites) and Model 2 (split Nd and O2 sites). Furthermore, transport of oxygen through the material via the vacancy hopping mechanism will likely involve the nearest-neighbor oxygen atom sites in the Nd layer. Total oxygen stoichiometry values were in the range 5.51 ≤ δ ≤ 5.11. The tetragonal lattice parameters increased with temperature as expected. But, the a-axis expands while the c-axis contracts with decreasing pO2 at a given temperature due to increasing vacancy concentration in the Nd layer.},
doi = {10.1039/c3ta01308a},
url = {https://www.osti.gov/biblio/1143576}, journal = {Journal of Materials Chemistry. A},
issn = {2050-7488},
number = 9,
volume = 1,
place = {United States},
year = {2013},
month = {1}
}