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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
Two coexisting vortex phases in the peak effect regime in a superconductor.
M Marchevsky1, M J Higgins, S Bhattacharya
1NEC Research Institute, Princeton, New Jersey 08540, USA. marchev@research.nj.nec.com
Nature
|February 24, 2001
Summary
The peak effect in superconductors like NbSe2 is explained by two coexisting vortex-matter phases with different pinning strengths. This phase coexistence drives a disorder-driven transition, resolving a 40-year-old mystery.
Area of Science:
- Condensed matter physics
- Superconductivity research
- Materials science
Background:
- Type-II superconductors exhibit a critical current anomaly near the superconductor-to-normal-metal transition, known as the peak effect.
- This peak effect, where critical current peaks before vanishing, has remained unexplained for 40 years.
Purpose of the Study:
- To investigate the underlying mechanism of the peak effect in NbSe2.
- To visualize the real-space distribution of critical current in the vortex phase.
Main Methods:
- Utilized a scanning a.c. Hall microscope.
- Visualized the real-space distribution of critical current in NbSe2.
Main Results:
- Identified two distinct vortex-matter phases with different pinning strengths coexisting on a macroscopic scale in the peak-effect regime.
- Demonstrated that the composition and transformation of these phases explain history effects and anomalous voltage responses.
Conclusions:
- The coexistence of two vortex-matter phases is responsible for the peak effect in NbSe2.
- This phase coexistence is a hallmark of a disorder-driven, non-thermal phase transition.
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