Vortex image


Superconducting vortices in random pinning

Ideal superconductors carry current without resistance and perfectly expel externally applied magnetic fields. The superconductivity is destroyed when too great a magnetic field is applied, and the material becomes a normal resistive conductor. Type-II materials remain superconducting in high magnetic fields by allowing the magnetic flux to penetrate the material in the form of discrete quantized vortices which repel each other and interact with defects in the superconducting material. The superconducting material returns to its normal resistive state only at the center of these vortices; the remainder of the material still carries a supercurrent. The vortices experience a Lorentz force from the flowing current and move through the superconductor until they are trapped, or pinned, at defect sites. Using molecular dynamics simulations, we explore the microscopic dynamics of vortices interacting with randomly arranged pinning sites under many conditions.

Preprints:

  1. Using principal component analysis to distinguish different dynamic phases in superconducting vortex matter
    C.J.O. Reichhardt, D. McDermott, and C. Reichhardt
    arXiv
    Vortices in type-II superconductors driven over random disorder are known to exhibit a remarkable variety of distinct nonequilibrium dynamical phases that arise due to the competition between vortex-vortex interactions, the quenched disorder, and the drive. These include pinned states, elastic flows, plastic or disordered flows, and dynamically reordered moving crystal or moving smectic states. The plastic flow phases can be particularly difficult to characterize since the flows are strongly disordered. Here we perform principal component analysis (PCA) on the positions and velocities of vortex matter moving over random disorder for different disorder strengths and drives. We find that PCA can distinguish the known dynamic phases as well as or better than previous measures based on transport signatures or topological defect densities. In addition, PCA recognizes distinct plastic flow regimes, a slowly changing channel flow and a moving amorphous fluid flow, that do not produce distinct signatures in the standard measurements. Our results suggest that this position and velocity based PCA approach could be used to characterize dynamic phases in a broader class of systems that exhibit depinning and nonequilibrium phase transitions.


Papers:

  1. Kibble-Zurek scenario and coarsening across nonequilibrium phase transitions in driven vortices and skyrmions
    C. Reichhardt and C.J.O. Reichhardt
    Phys. Rev. Res. 5, 033221 (2023). arXiv


  2. Kibble-Zurek mechanism for nonequilibrium phase transitions in driven systems with quenched disorder
    C.J.O. Reichhardt, A. del Campo, and C. Reichhardt
    Commun. Phys. 5, 173 (2022). arXiv


  3. Jamming, fragility and pinning phenomena in superconducting vortex systems
    C. Reichhardt and C.J.O. Reichhardt
    Sci. Rep. 10, 11625 (2020). arXiv


  4. Devil's staircase and disordering transitions in sliding vortices and Wigner crystals on random substrates with transverse driving
     C. Reichhardt and C.J. Olson Reichhardt
    Phys. Rev. B 76, 214305 (2007). arXiv


  5. Probing vortex systems with individual vortex manipulation
    C.J. Olson Reichhardt and C. Reichhardt
    Physica C 460-462, 1284 (2007).


  6. Statics and dynamics of two-dimensional vortex liquid crystals
    C. Reichhardt and C.J. Olson Reichhardt
    Europhys. Lett. 75, 489 (2006). arXiv


  7. Dynamical behaviors of quasi-1D vortex states: Possible applications to the vortex chain state
    C. Reichhardt and C.J. Olson Reichhardt
    Phys. Rev. B 66, 172504 (2002). arXiv


  8. Critical depinning force and vortex lattice order in disordered superconductors
    C.J. Olson, C. Reichhardt, and S. Bhattacharya
    Phys. Rev. B 64, 024518 (2001). arXiv


  9. Transverse depinning in strongly driven vortex lattices with disorder
    C.J. Olson and C. Reichhardt
    Phys. Rev. B 61, R3811 (2000). arXiv


  10. Dynamic vortex phases and pinning in superconductors with twin boundaries
     C. Reichhardt, C.J. Olson, and F. Nori
    Phys. Rev. B 61, 3665 (2000). arXiv


  11. Topological invariants in microscopic transport on rough landscapes: Morphology, hierarchical structure, and Horton analysis of riverlike networks of vortices
     A.P. Mehta, C. Reichhardt, C.J. Olson, and F. Nori
    Phys. Rev. Lett. 82, 3641 (1999). arXiv


  12. Nonequilibrium dynamic phase diagram for vortex lattices
     C.J. Olson, C. Reichhardt, and F. Nori
    Phys. Rev. Lett. 81, 3757 (1998). arXiv


  13. Fractal networks, braiding channels, and voltage noise in intermittently flowing rivers of quantized magnetic flux
     C.J. Olson, C. Reichhardt, and F. Nori
    Phys. Rev. Lett. 80, 2197 (1998). arXiv


  14. Plastic flow, voltage noise and vortex avalanches in superconductors
     C.J. Olson, C. Reichhardt, J. Groth, S.B. Field, and F. Nori
    Physica C 290, 89 (1997). arXiv


  15. Superconducting vortex avalanches, voltage bursts, and vortex plastic flow: Effect of the microscopic pinning landscape on the macroscopic properties
     C.J. Olson, C. Reichhardt, and F. Nori
    Phys. Rev. B 56, 6175 (1997). arXiv


  16. Vortex plastic motion in twinned superconductors
     J. Groth, C. Reichhardt, C.J. Olson, S.B. Field, and F. Nori
    Phys. Rev. Lett. 77, 3625 (1996). arXiv


  17. Microscopic derivation of magnetic-flux-density profiles, magnetization hysteresis loops, and critical currents in strongly pinned superconductors
     C. Reichhardt, C.J. Olson, J. Groth, S. Field, and F. Nori
    Phys. Rev. B 52, 10441 (1995). arXiv

Last modified May 3, 2018