Twin-Boundary Pinning of Superconducting Vortex Arrays

TL;DR

This paper investigates how twin planes in high-temperature superconductors influence magnetic flux line dynamics, revealing regimes dominated by superkink excitations and the impact of rare regions and field tilting on transport properties.

Contribution

It introduces a detailed analysis of flux motion in the presence of twin planes, including the effects of rare regions and field tilt, extending understanding beyond previous models.

Findings

Superkink excitations dominate flux dynamics in certain regimes.

Rare regions can significantly impede flux transport in long samples.

Tilted magnetic fields strongly affect resistivity due to flux motion.

Abstract

We discuss the low-temperature dynamics of magnetic flux lines in high-temperature superconductors in the presence of a family of parallel twin planes that contain the $c$ axis. A current applied along the twin planes drives flux motion in the direction transverse to the planes and acts like an electric field applied to {\it one-dimensional} carriers in disordered semiconductors. As in flux arrays with columnar pins, there is a regime where the dynamics is dominated by superkink excitations that correspond to Mott variable range hopping (VRH) of carriers. In one dimension, however, rare events, such as large regions void of twin planes, can impede VRH and dominate transport in samples that are sufficiently long in the direction of flux motion. In short samples rare regions can be responsible for mesoscospic effects. The phase boundaries separating various transport regimes are discussed. The effect of tilting the applied field out of the twin planes is also considered. In this case the resistivity from flux motion is found to depend strongly on the tilt angle.