Critical vortex line length near a zigzag of pinning centers

TL;DR

This paper investigates how a vortex line in a superconductor elongates and depins when navigating a zigzag array of pinning centers, using Ginzburg-Landau theory to analyze the critical length and transition.

Contribution

It introduces a detailed analysis of vortex line length growth and depinning behavior near a zigzag of insulating pinning spheres within a superconductor.

Findings

Vortex line length increases with zigzag complexity.

Identification of the depinning transition point.

Quantitative relation between defect geometry and vortex behavior.

Abstract

A vortex line passes through as many pinning centers as possible on its way from one extremety of the superconductor to the other at the expense of increasing its self-energy. In the framework of the Ginzburg-Landau theory we study the relative growth in length, with respect to the straight line, of a vortex near a zigzag of defects. The defects are insulating pinning spheres that form a three-dimensional cubic array embedded in the superconductor. We determine the depinning transition beyond which the vortex line no longer follows the critical zigzag path of defects.