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Theory of plastic vortex creep
1Argonne National Laboratory, Materials Science Division, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
Physical Review Letters
|December 2, 2000
Summary
We present a theory for plastic vortex creep in type-II superconductors, explaining how dislocation dynamics influence creep rates. This model clarifies the transition from ordered to disordered vortex phases and the second peak effect.
Area of Science:
- Condensed matter physics
- Superconductivity
- Materials science
Background:
- Type-II superconductors exhibit complex vortex matter phases.
- Understanding vortex creep is crucial for superconductor applications.
- Dislocation dynamics play a key role in plastic deformation of vortex solids.
Purpose of the Study:
- To develop a theory for plastic vortex creep in topologically disordered vortex solids.
- To explain the influence of driven thermally activated dislocation dynamics on creep.
- To investigate the relationship between creep rate, driving current, and phase transitions.
Main Methods:
- Theoretical modeling of dislocation dynamics.
- Analysis of plastic barriers and their dependence on driving current.
- Application of concepts from disordered elastic media on random substrates.
Main Results:
- A power-law divergence of plastic barriers U(pl)(j) ~ j(-μ) was derived.
- Specific values for μ were found: μ=1 for single dislocations and μ=2/5 for dislocation bundles.
- A suppression of creep rate at the ordered-to-disordered phase transition was predicted.
Conclusions:
- The theory provides a framework for understanding plastic vortex creep in type-II superconductors.
- The results explain the observed increase in apparent critical current (second peak effect).
- The approach is applicable to general dynamics of disordered elastic media.
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