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Title: Atomic-resolution imaging of electrically induced oxygen vacancy migration and phase transformation in SrCoO 2.5-σ

Oxygen ion transport is the key issue in redox processes. Visualizing the process of oxygen ion migration with atomic resolution is highly desirable for designing novel devices such as oxidation catalysts, oxygen permeation membranes, and solid oxide fuel cells. We show the process of electrically induced oxygen migration and subsequent reconstructive structural transformation in a SrCoO 2.5-σ film by scanning transmission electron microscopy. We find that the extraction of oxygen from every second SrO layer occurs gradually under an electrical bias; beyond a critical voltage, the brownmillerite units collapse abruptly and evolve into a periodic nano-twined phase with a high c/a ratio and distorted tetrahedra. These results show that oxygen vacancy rows are not only natural oxygen diffusion channels, but also preferred sites for the induced oxygen vacancies. These direct experimental results of oxygen migration may provide a common mechanism for the electrically induced structural evolution of oxides.
Authors:
 [1] ;  [2] ;  [2] ;  [3] ;  [3] ;  [4] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [10] ;  [11]
  1. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics, Inst. of Physics; Tsinghua Univ., Beijing (China). School of Materials Science and Engineering
  2. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics, Inst. of Physics
  3. Tsinghua Univ., Beijing (China). State Key Lab. of Low-Dimensional Quantum Physics
  4. Zhejiang Univ., Hangzhou (China).. Center of Electron Microscopy and State Key Lab. of Silicon Materials
  5. Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering
  6. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Engineering
  7. DENSsolutions, Delft (The Netherlands)
  8. Tsinghua Univ., Beijing (China). State Key Lab. of Low-Dimensional Quantum Physics; Collaborative Innovation Center of Quantum Matter, Beijing (China); RIKEN, Saitama (Japan). Center for Emergent Matter Science (CEMS)
  9. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics, Inst. of Physics; Collaborative Innovation Center of Quantum Matter, Beijing (China); Univ. of Chinese Academy of Sciences, Beijing (China). School of Physical Sciences
  10. Chinese Academy of Sciences (CAS), Beijing (China). Beijing National Lab. for Condensed Matter Physics, Inst. of Physics; Univ. of Chinese Academy of Sciences, Beijing (China). School of Physical Sciences
  11. Tsinghua Univ., Beijing (China). School of Materials Science and Engineering
Publication Date:
Grant/Contract Number:
FG02-07ER46417
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 8; Journal Issue: 1; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Pennsylvania State Univ., University Park, PA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; imaging techniques; phase transitions and critical phenomena
OSTI Identifier:
1392943