Peak Effect and the Transition from Elastic to Plastic Depinning

TL;DR

This paper reports the first simulation observation of the peak effect in magnetic vortices, linking it to a transition from elastic to plastic depinning and showing defect production can enhance pinning.

Contribution

It introduces a novel simulation approach by tuning the shear modulus with a fictitious potential to study the peak effect in vortex lattices.

Findings

Peak effect is most pronounced at low pinning densities.

Peak effect correlates with elastic to plastic depinning transition.

Defect production can enhance vortex lattice pinning.

Abstract

We demonstrate for the first time an observation of the peak effect in simulations of magnetic vortices in a superconductor. The shear modulus $c_{66}$ of the vortex lattice is tuned by adding a fictitious {attractive} short range potential to the usual long-range repulsion between vortices. The peak effect is found to be most pronounced in low densities of pinning centers, and is always associated with a transition from elastic to plastic depinning. The simulations suggest in some situations that over a range of values of $c_{66}$ the production of lattice defects by a driving force enhances the pinning of the lattice.