Dynamical regimes of vortex flow in type-II superconductors with parallel twin boundaries

TL;DR

This study investigates the complex dynamics of vortex flow in disordered type-II superconductors with parallel twin boundaries, revealing various regimes and topological excitations through simulations of driven flux lines.

Contribution

It introduces a detailed simulation approach to analyze vortex dynamics in the presence of twin boundaries, highlighting new dynamical regimes and flux line excitations.

Findings

Identification of multiple dynamical regimes near depinning transition

Emergence of preferred lattice orientation due to planar defect pinning

Direct measurement of flux line excitations like half-loops and double kinks

Abstract

We explore the dynamics of driven magnetic flux lines in disordered type-II superconductors in the presence of twin boundaries oriented parallel to the direction of the applied magnetic field, using a three-dimensional elastic line model simulated with Langevin molecular dynamics. The lines are driven perpendicular to the planes to model the effect of an electric current applied parallel to the planes and perpendicular to the magnetic field. A study of the long-time non-equilibrium steady states for varying sample orientation and thickness reveals a rich collection of dynamical regimes spanning the depinning crossover region that separates the pinned and moving-lattice states of vortex matter. We observe the emergence of a preferred direction for the ordering of the Abrikosov lattice in the free-flowing vortex regime due to asymmetric pinning by the planar defects. We have performed novel direct measurements of flux line excitations such as half-loops and double kinks to aid the characterization of the topologically rich flux flow profile.