Irreversible flow of vortex matter: polycrystal and amorphous phases

Abstract

We investigate the microscopic mechanisms giving rise to plastic depinning and irreversible flow in vortex matter. The topology of the vortex array crucially determines the flow response of this system. To illustrate this claim, two limiting cases are considered: weak and strong pinning interactions. In the first case disorder is strong enough to introduce plastic effects in the vortex lattice. Diffraction patterns unveil polycrystalline lattice topology with dislocations and grain boundaries determining the electromagnetic response of the system. Filamentary flow is found to arise as a consequence of dislocation dynamics. We analize the stability of vortex lattices against the formation of grain boundaries, as well as the steady state dynamics for currents approaching the depinning critical current from above, when vortex motion is mainly localized at the grain boundaries. On the contrary, a dislocation description proves no longer adequate in the second limiting case examined. For strong pinning interactions, the vortex array appears completely amorphous and no remnant of the Abrikosov lattice order is left. Here we obtain the critical current as a function of impurity density, its scaling properties, and characterize the steady state dynamics above depinning. The plastic depinning observed in the amorphous phase is tightly connected with the emergence of channel-like flow. Our results suggest the possibility of establishing a clear distinction between two topologically disordered vortex phases: the vortex polycrystal and the amorphous vortex matter.

13 pages, 16 figures

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Cited by in corpus (5)

• Statics and Dynamics of Skyrmions Interacting with Pinning: A Review
• How the vortex lattice of a superconductor becomes disordered: a study by scanning tunneling spectroscopy
• Scale-free phase field theory of dislocations
• Nonlinear Transport, Dynamic Ordering, and Clustering for Driven Skyrmions on Random Pinning
• Viscoelastic Interfaces Driven in Disordered Media and Applications to Friction