Formation of structural defects and strain in electrodegraded Fe‐doped SrTiO3 crystals due to oxygen vacancy migration
Abstract
We report on our investigation of structural defect and strain formation in electrodegraded reduced and oxidized, Fe‐doped SrTiO3 (Fe:STO) single crystals using optical second harmonic generation (SHG) and confocal Raman spectroscopy. SHG and Raman spectra reveal structural and electrochemical inhomogeneity resulting from the formation of Fe4+/oxygen ion and Fe3+/oxygen vacancy aggregation sites along the degraded anode and cathode interfaces, respectively. We show that mixed Fe3+/Fe4+ states and structural strain gradients are generated across the color fronts. These results, as well as oxygen sublattice differences between the anodic and cathodic bulk, present the color front as an interface between two dominant oxygen bonding distortions. The strain near the color front shows a strong dependence on oxygen vacancy concentration and diffusion within the crystals. Our characterization of structural and electrochemical changes due to electric field‐induced strain and oxygen vacancy migration advances knowledge of electrodegradation in perovskite‐based titanate single crystals.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 06, 2018
- Source ID
- 10.1111/jace.15407
Entities
People
- Clive A. Randall
- David Ascienzo
- Onur Kurt
- Russell A. Maier
- Steven Greenbaum
- Thorsten J M Bayer
- Yuhang Ren
Organizations
- Air Force Office of Scientific Research
- City College of New York
- City University of New York
- Hunter College
- Pennsylvania State University