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We examine metastable and transient effects both above and below the first-order disorder driven decoupling line in a 3D simulation of magnetically interacting pancake vortices. We observe pronounced transient and history effects as well as…

Superconductivity · Physics 2009-05-15 C. J. Olson , C. Reichhardt , R. T. Scalettar , G. T. Zimanyi , N. Gronbech-Jensen

Order-disorder transitions are widely explored in various vortex structures in condensed matter physics, i.e., in the type-II superconductors and Bose-Einstein condensates. In this study, we have investigated the ordering of the polar…

We study vortex clustering in type II Superconductors. We demonstrate that the ``second peak'' observed in magnetisation loops may be a dynamical effect associated with a density driven instability of the vortex system. At the microscopic…

Superconductivity · Physics 2009-10-31 D. K. Jackson , M. Nicodemi , G. Perkins , N. A. Lindop , Henrik Jeldtoft Jensen

Using numerical simulations of magnetically interacting vortices in disordered layered superconductors we obtain the static vortex phase diagram as a function of magnetic field and temperature. For increasing field or temperature, we find a…

Superconductivity · Physics 2009-10-31 C. J. Olson , C. Reichhardt , R. T. Scalettar , G. T. Zimanyi , N. Gronbech-Jensen

Dynamic ordering of driven vortex matter has been investigated in the peak effect regime of both amorphous MoGe films and 2H-NbSe2 crystals by mode locking (ML) and dc transport measurements. ML features allow us to trace how the shear…

Superconductivity · Physics 2007-06-15 N. Kokubo , T. Asada , K. Kadowaki , K. Takita , 1 T. G. Sorop , P. H. Kes

In single crystals of 2H-NbSe2, we identify for the first time a crossover from weak collective to strong pinning regime in the vortex state which is not associated with the peak effect phenomenon. Instead, we find the crossover is…

Superconductivity · Physics 2007-05-23 Shyam Mohan , Jaivardhan Sinha , S. S. Banerjee , Yuri Myasoedov

A study of path dependent effects in single crystals of CeRu2 and 2H-NbSe2 show that critical current density Jc of the vortex state depends on its thermomagnetic history over a very large part of (H,T) parameter space. The path dependence…

Superconductivity · Physics 2007-05-23 G. Ravikumar

The flux line lattice melting transition in two-dimensional pure and disordered superconductors is studied by a Monte Carlo simulation using the lowest Landau level approximation and quasi-periodic boundary condition on a plane. The…

Superconductivity · Physics 2009-11-07 Mai Suan Li , Thomas Nattermann

We report on transport and ac susceptibility studies below the peak effect in twinned YBa2Cu3O7 single crystals. We find that disorder generated at the peak effect can be partially inhibited by forcing vortices to move with an ac driving…

Superconductivity · Physics 2009-11-07 Sergio O. Valenzuela , Boris Maiorov , Eduardo Osquiguil , Victoria Bekeris

We investigate the order - disorder transition line from a Bragg glass to an amorphous vortex glass in the H-T phase diagram of three-dimensional type-II superconductors with account of both pinning-caused and thermal fluctuations of the…

Superconductivity · Physics 2009-11-07 Grigorii P. Mikitik , Ernst Helmut Brandt

A field theoretical method is developed which permits us to study the dynamics of vortices in disordered environments. In particular, we obtain a self-consistent system of equations for disorder averaged quantities. Making use of a…

Condensed Matter · Physics 2009-10-28 J. Müllers , A. Schmid

The stability and the critical properties of the three-dimensional vortex-glass order in random type-II superconductors with point disorder is investigated in the unscreened limit based on a lattice {\it XY} model with a uniform field. By…

Superconductivity · Physics 2009-11-10 Hikaru Kawamura

We present magnetization data on a weakly pinned CeRu_2 single crystal showing the existence of a stable state of the vortex lattice in the peak effect region. The stable state is achieved by cycling the magnetic field by small amplitude.…

Scanning tunneling experiments on single crystals of superconducting FeTe$_{0.55}$Se$_{0.45}$ have recently provided evidence for discrete energy levels inside vortices. Although predicted long ago, such levels are seldom resolved due to…

Superconductivity · Physics 2018-10-29 Christophe Berthod

We report experimental evidence of strong orientational coupling between the crystal lattice and the vortex lattice in a weakly pinned Co-doped NbSe2 single crystal through direct imaging using low temperature scanning tunneling…

The stability of the three-dimensional vortex-glass order in random type-II superconductors with point disorder is investigated by equilibrium Monte Carlo simulations based on a lattice XY model with a uniform field threading the system. It…

Superconductivity · Physics 2009-10-31 Hikaru Kawamura

We report structural evidence of dynamic reorganization in vortex matter in clean NbSe$_2$ by joint small angle neutron scattering and ac-susceptibility measurements. The application of oscillatory forces in a transitional region near the…

Superconductivity · Physics 2015-08-12 M. Marziali Bermúdez , M. R. Eskildsen , M. Bartkowiak , G. Nagy , V. Bekeris , G. Pasquini

We present a mode locking (ML) phenomenon of vortex matter observed around the peak effect regime of 2H-NbSe$_2$ pure single crystals. The ML features allow us not only to trace how the shear rigidity of driven vortices persists on…

Superconductivity · Physics 2007-05-23 N. Kokubo , K. Kadowaki , K. Takita

We use Monte Carlo simulations of the 3D uniformly frustrated XY model, with uncorrelated quenched randomness in the in-plane couplings, to model the effect of random point pins on the vortex line phases of a type II superconductor. We map…

Superconductivity · Physics 2009-10-31 P. Olsson , S. Teitel

We present the results of a study of vortex arrangements in the peak-effect regime of 2H-NbSe_2 by scanning tunneling microscopy. By slowly increasing the temperature in a constant magnetic field, we observed a sharp transition from…

Superconductivity · Physics 2009-11-07 A. M. Troyanovski , M. van Hecke , N. Saha , J. Aarts , P. H. Kes