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Tuning Oxide Properties by Oxygen Vacancy Control During Growth and Annealing
Published on: June 9, 2023
How metallic Fe controls the composition of its native oxide
Sebastien Couet1, Kai Schlage, Karel Saksl
1Deutsches Elektronen Synchrotron (DESY), Notkestrasse 85, Hamburg, Germany. sebastien.couet@desy.de
Physical Review Letters
|September 4, 2008
Summary
We studied iron oxidation and found that native iron oxide retains metallic iron. Depositing more iron fully reduces the oxide to an FeO-like structure with only Fe2+ sites.
Area of Science:
- Materials Science
- Surface Science
- Chemistry
Background:
- Ultrathin iron layers are susceptible to oxidation.
- Understanding the chemical states during oxidation and deposition is crucial for materials development.
Purpose of the Study:
- To investigate the in situ oxidation of ultrathin iron layers.
- To monitor chemical changes during subsequent iron metal deposition.
- To quantify layer composition during these processes.
Main Methods:
- Hard x-ray absorption spectroscopy was used for in situ analysis.
- The site-sensitive nature of the technique enabled quantitative composition monitoring.
Main Results:
- Native iron oxide incorporates a significant fraction of metallic iron atoms.
- Even in a saturated oxide state, metallic iron persists.
- Subsequent iron deposition completely reduces the oxide.
- The reduced oxide forms an FeO-like structure with only Fe2+ sites.
Conclusions:
- The oxidation process of ultrathin iron layers is complex, with metallic iron remaining even in the oxide.
- Iron deposition effectively reduces the oxide, forming a well-defined FeO-like phase.
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