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Metallic normal state of Y1Ba2Cu3O(7-delta)
1Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA.
Physical Review Letters
|September 16, 2000
Summary
Investigating flux flow down to 2% of T(c), this study reveals that vortex dissipation remains conventional as temperature approaches absolute zero. The normal state is metallic, not insulating, with residual resistivity saturating at low temperatures.
Area of Science:
- Condensed Matter Physics
- Superconductivity Research
Background:
- Flux-vortex pinning is a key phenomenon in superconductors.
- Understanding flux flow dynamics at low temperatures is crucial for fundamental physics.
Purpose of the Study:
- To investigate flux flow behavior across the entire temperature range, down to 2% of the critical temperature (T(c)).
- To determine the nature of the normal state and vortex dissipation mechanisms as temperature approaches absolute zero.
Main Methods:
- Utilizing intense pulsed current densities to overcome flux-vortex pinning.
- Studying resistivity measurements over a wide temperature range.
Main Results:
- Resistivity at high vortex velocities is proportional to magnetic field (B) and follows rho approximately rho(n)B/H(c2).
- The normal state resistivity (rho(n)) saturates to a finite residual value as T-->0, indicating a metallic state.
- Vortex dissipation mechanisms remain conventional even at temperatures approaching absolute zero.
Conclusions:
- The normal state of the superconductor is metallic, not insulating.
- Vortex dissipation continues to be a conventional process at very low temperatures.
- The findings challenge previous speculations about the normal state and low-temperature dissipation.