Relaxation dynamics of vortex lines in disordered type-II superconductors following magnetic field and temperature quenches

TL;DR

This study investigates how rapid temperature and magnetic field changes affect the non-equilibrium relaxation and aging behavior of vortex lines in disordered type-II superconductors using simulations with different defect types.

Contribution

It introduces a detailed simulation approach to analyze vortex line relaxation after quenches, distinguishing effects of point-like versus columnar defects on aging dynamics.

Findings

Different defect types influence vortex pinning and relaxation.

Steady-state properties are characterized by gyration radius and pinned fraction.

Two-time correlation functions reveal complex aging behaviors.

Abstract

We study the effects of rapid temperature and magnetic field changes on the non-equilibrium relaxation dynamics of magnetic vortex lines in disordered type-II superconductors by employing an elastic line model and performing Langevin molecular dynamics simulations. In a previously equilibrated system, either the temperature is suddenly changed, or the magnetic field is instantaneously altered which is reflected in adding or removing flux lines to or from the system. The subsequent aging properties are investigated in samples with either randomly distributed point-like or extended columnar defects, which allows to distinguish the complex relaxation features that result from either type of pinning centers. One-time observables such as the radius of gyration and the fraction of pinned line elements are employed to characterize steady-state properties, and two-time correlation functions such as the vortex line height autocorrelations and their mean-square displacement are analyzed to study the non-linear stochastic relaxation dynamics in the aging regime.