Vortex dynamics and defects in simulated flux flow

M. Faleski, M. Marchetti, A. Middleton

Research output: Contribution to journalArticlepeer-review

128 Scopus citations

Abstract

We present the results of molecular dynamic simulations of a two-dimensional vortex array driven by a uniform current through random pinning centers at zero temperature. We identify two types of flow of the driven array near the depinning threshold. For weak disorder the flux array contains few dislocation and moves via correlated displacements of patches of vortices in a crinkle motion. As the disorder strength increases, we observe a crossover to a spatially inhomogeneous regime of plastic flow, with a very defective vortex array and a channel-like structure of the flowing regions. The two regimes are characterized by qualitatively different spatial distributions of vortex velocities. In the crinkle regime the distribution of vortex velocities near threshold has a single maximum that shifts to larger velocities as the driving force is increased. In the plastic regime the distribution of vortex velocities near threshold has a clear bimodal structure that persists upon time averaging the individual velocities. The bimodal structure of the velocity distribution reflects the coexistence of pinned and flowing regions and is proposed as a quantitative signature of plastic flow.

Original languageEnglish (US)
Pages (from-to)12427-12436
Number of pages10
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume54
Issue number17
DOIs
StatePublished - 1996

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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