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

摘要

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