Collective pinning of imperfect vortex lattices by material line defects in extreme type-II superconductors

TL;DR

This paper predicts how the critical current density in extreme type-II superconductors depends on magnetic field and defect structure, aligning with experimental data for high-temperature superconductors.

Contribution

It introduces a theoretical model for vortex pinning by line and point defects, explaining the field and thickness dependence of critical current density in superconductors.

Findings

Critical current density follows an inverse square-root law with magnetic field.

Inclusion of point defect pinning adds an inverse thickness dependence.

Model shows moderate agreement with experimental data at liquid-nitrogen temperature.

Abstract

The critical current density shown by a superconductor at the extreme type-II limit is predicted to follow an inverse square-root power law with external magnetic field if the vortex lattice is weakly pinned by material line defects. It acquires an additional inverse dependence with thickness along the line direction once pinning of the interstitial vortex lines by material point defects is included. Moderate quantitative agreement with the critical current density shown by second-generation wires of high-temperature superconductors in kG magnetic fields is achieved at liquid-nitrogen temperature.