Untangling surface oxygen exchange effects in YBa2Cu3O6+x thin films by electrical conductivity relaxation
P Cayado1, C F Sánchez-Valdés1, A Stangl1
1Institut de Ciència de Materials de Barcelona (CSIC), Campus UAB, 08193, Bellaterra, Catalonia, Spain. Xavier.obradors@icmab.es.
Physical Chemistry Chemical Physics : PCCP
|May 20, 2017
Summary
This study investigated oxygen diffusion in Yttrium Barium Copper Oxide (YBCO) films. Oxygen incorporation is limited by surface exchange, but silver coatings can accelerate this process at lower temperatures.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Thin Film Technology
Background:
- Yttrium Barium Copper Oxide (YBCO) is a crucial superconductor.
- Understanding oxygen diffusion kinetics is vital for optimizing YBCO properties.
- Epitaxial YBCO thin films are typically prepared via chemical solution deposition (CSD).
Purpose of the Study:
- To investigate the kinetics of oxygen incorporation and excorporation in YBCO epitaxial thin films.
- To identify the rate-limiting step in the oxygenation process.
- To develop strategies for accelerating oxygenation kinetics.
Main Methods:
- Electrical conductivity relaxation measurements were employed.
- Experiments were conducted on YBCO thin films prepared by the trifluoroacetate CSD route.
- The influence of temperature and oxygen partial pressure on kinetics was analyzed.
Main Results:
- Oxygenation kinetics in YBCO films are primarily limited by the surface exchange of oxygen molecules, not bulk diffusion.
- The study elucidated the oxygen surface exchange mechanism and identified the rate-determining step.
- Silver (Ag) coatings were found to catalyze the oxygenation process.
Conclusions:
- The surface exchange process is the bottleneck for oxygen diffusion in YBCO films.
- A strategy using Ag coatings effectively accelerates oxygenation kinetics at reduced temperatures.
- This facilitates lower-temperature processing for YBCO thin films.
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