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Evidence for a minigap in YBCO grain boundary Josephson junctions
P Lucignano1, D Stornaiuolo, F Tafuri
1CNR-SPIN, Monte S. Angelo--via Cinthia, I-80126 Napoli, Italy.
Physical Review Letters
|January 15, 2011
Summary
Self-assembled YBaCuO Josephson junctions reveal resistance oscillations. These oscillations provide mesoscopic information about the minigap and quasiparticle behavior in the junction barrier.
Area of Science:
- Condensed Matter Physics
- Superconductivity
- Materials Science
Background:
- Self-assembled Yttrium Barium Copper Oxide (YBaCuO) diffusive grain boundary Josephson junctions represent a unique system for studying the proximity effect.
- In these junctions, normal state coherence dominates over superconducting coherence within the barrier region.
Purpose of the Study:
- To investigate the mesoscopic information encoded in the current-voltage characteristics of YBaCuO Josephson junctions.
- To analyze the nature and persistence of resistance oscillations and their relation to the induced minigap and quasiparticle dynamics.
Main Methods:
- Fabrication of self-assembled YBaCuO diffusive grain boundary submicron Josephson junctions.
- Measurement of current-voltage (I-V) characteristics to observe resistance oscillations.
- Analysis of the mesoscopic information derived from I-V curves, focusing on the minigap and quasiparticle properties.
Main Results:
- Observed resistance oscillations in the current-voltage characteristics of the Josephson junctions.
- Demonstrated that these oscillations encode mesoscopic information, specifically related to the minigap induced in the barrier.
- Confirmed the persistence of these oscillations at large voltages, indicating a long lifetime for antinodal quasiparticles.
Conclusions:
- Self-assembled YBaCuO Josephson junctions provide a platform for realizing a special regime of the proximity effect.
- Resistance oscillations are a valuable tool for probing mesoscopic phenomena and quasiparticle properties in superconducting junctions.
- The long lifetime of high-energy quasiparticles is evidenced by the robust nature of these oscillations.
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