Effect of the vortex core on the magnetic field in hard superconductors

TL;DR

This paper investigates how the finite size of vortex cores influences magnetic field measurements in hard superconductors, using analytical and numerical solutions of Ginzburg-Landau equations to explain recent experimental observations.

Contribution

It introduces new numerical solutions and emphasizes the importance of vortex core size in interpreting magnetic field data in superconductors.

Findings

Finite vortex core size significantly affects magnetic field measurements.

Proper modeling explains recent experimental observations.

Results highlight the importance of core size at low fields.

Abstract

Using approximate analytical and new numerical solutions of the conventional Ginzburg-Landau equations we calculate the small angle neutron scattering cross-section and the variance of the field distribution as measured by muon-spin rotation for superconductors with large Ginzburg-Landau parameter $\kappa$. Our results prove that a proper account of the finite size of the vortex core is important, even at relatively low fields. This finding provides a natural explanation for the recently observed field dependence of the CeRu_2 form factor and of the YBa_2Cu_3O_{6.95} penetration depth.