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Field dependence of the vortex core size in a multiband superconductor
F D Callaghan1, M Laulajainen, C V Kaiser
1Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada.
Physical Review Letters
|December 31, 2005
Summary
Muon spin rotation reveals how vortex core size in niobium diselenide (NbSe2) changes with magnetic fields. A model explains this core size change and its link to electronic thermal conductivity in superconductors.
Area of Science:
- Condensed matter physics
- Superconductivity research
Background:
- Superconductors exhibit unique quantum phenomena, including magnetic vortices.
- Understanding vortex core size is crucial for characterizing superconducting properties.
Purpose of the Study:
- To investigate the magnetic field dependence of vortex core size in the multiband superconductor niobium diselenide (NbSe2).
- To develop a model linking vortex core size dynamics to electronic thermal conductivity.
Main Methods:
- Muon spin rotation (µSR) measurements were employed to probe the vortex core size.
- Analysis focused on the behavior of quasiparticle core states associated with different superconducting gaps.
Main Results:
- A rapid, field-induced shrinkage of the vortex core size was observed at low magnetic fields in NbSe2.
- The core size became field-independent at higher fields (above 4 kOe) due to the nature of the larger superconducting gap.
- A proposed model accurately describes the relationship between reduced core size and enhanced electronic thermal conductivity.
Conclusions:
- The study elucidates the distinct contributions of multiband superconductivity to vortex core size behavior.
- The developed model provides a unified explanation for NbSe2 and single-band superconductor V3Si, highlighting a fundamental link between vortex dynamics and thermal transport.