Field Dependent Coherence Length in the Superclean, High-Kappa Superconductor CeCoIn5

TL;DR

This study investigates the flux-line lattice in CeCoIn5 using neutron scattering, revealing a field-independent form factor and a first-order transition, indicating a strongly field-dependent coherence length in this superclean superconductor.

Contribution

It provides experimental evidence of a field-dependent coherence length and unusual FLL behavior in CeCoIn5, supporting recent theoretical models for high-kappa superconductors.

Findings

First-order FLL symmetry transition at ~0.55 T

FLL form factor remains constant with magnetic field

Evidence of a strongly field-dependent coherence length

Abstract

Using small-angle neutron scattering, we have studied the flux-line lattice (FLL) in superconducting CeCoIn5. The FLL is found to undergo a first-order symmetry and reorientation transition at ~0.55 T at 50 mK. The FLL form factor in this material is found to be independent of the applied magnetic field, in striking contrast to the exponential decrease usually observed in superconductors. This result is consistent with a strongly field-dependent coherence length in CeCoIn5, in agreement with recent theoretical predictions for superclean, high-kappa superconductors.