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Interplay between static and dynamic properties of semifluxons in YBa2Cu3O(7-delta) 0-pi Josephson junctions
K Cedergren1, J R Kirtley, T Bauch
1Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Physical Review Letters
|May 21, 2010
Summary
We studied long YBa2Cu3O(7-delta) 0-pi Josephson junctions, finding semifluxons and unique fluxon-semifluxon interactions. These differ from conventional 0 junctions, impacting their dynamic properties.
Area of Science:
- Superconductivity
- Condensed Matter Physics
- Quantum Electronics
Background:
- Josephson junctions are crucial for quantum electronic devices.
- 0-pi Josephson junctions offer unique quantum properties compared to conventional 0 junctions.
- Understanding fluxon dynamics is key to controlling Josephson junction behavior.
Purpose of the Study:
- To investigate static and dynamic properties of long YBa2Cu3O(7-delta) 0-pi Josephson junctions.
- To compare these properties with conventional 0 junctions.
- To elucidate the nature of observed phenomena like zero field steps.
Main Methods:
- Fabrication and characterization of YBa2Cu3O(7-delta) 0-pi and 0 Josephson junctions.
- Scanning Superconducting Quantum Interference Device (SQUID) microscopy for imaging.
- Analysis of current-voltage characteristics.
- Comparison with numerical simulations.
Main Results:
- Scanning SQUID microscopy revealed semifluxons at phase discontinuity points in 0-pi junctions.
- Zero field steps were observed in all investigated junctions.
- Simulations attributed zero field steps to fluxon travel in 0 junctions.
- Fluxon-semifluxon interactions were identified as the cause of these steps in 0-pi junctions.
Conclusions:
- 0-pi Josephson junctions exhibit distinct dynamic properties due to semifluxon presence.
- Fluxon-semifluxon interactions govern the behavior of 0-pi junctions, differing from fluxon dynamics in 0 junctions.
- These findings advance the understanding of complex Josephson junction behavior for potential applications.
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