Related papers: Study of Vortex Dynamics and Phase Transitions in …
We have studied vortex pinning and dynamics in a Sr0.6K0.4Fe2As2 superconducting tape with critical current density Jc~0.1 MA/cm2 at 4.2 K and 10 T. It is found that grain boundary pinning is dominant in the vortex pinning mechanism.…
Quantum fluids refer to a class of systems that remain in fluid state down to absolute zero temperature. In this letter, using a combination of magnetotransport and scanning tunneling spectroscopy down to 300 mK, we show that vortices in a…
We characterize the mechanisms of vortex pinning in a superfluid thin film described by the two-dimensional Gross-Pitaevskii equation. We consider a vortex "scattering experiment" whereby a single vortex in a superfluid flow interacts with…
A gel consists of a network of particles or molecules formed for example using the sol-gel process, by which a solution transforms into a porous solid. Particles or molecules in a gel are mainly organized on a scaffold that makes up a…
We review our studies of elastic lattices driven by an external force $F$ in the presence of random disorder, which correspond to the case of vortices in superconducting thin films driven by external currents. Above a critical force $F_c$…
The response of superconducting devices to electromagnetic radiation is a core concept implemented in diverse applications, ranging from the currently used voltage standard to single photon detectors in astronomy. Suprisingly, a…
Melting of moving vortex lattices in clean superconducting films with periodic pinning is studied by a dynamical "cage" model, based on a mean-field treatment of Langevin's equations for the whole vortex lattice, assuming elastic flow. In…
Spontaneous nucleation and the consequent penetration of vortices into thin superconducting films and wires, subjected to a magnetic field, can be considered as a nonlinear stage of primary instability of the current-carrying…
A simulation study using the time-dependent Ginzburg-Landau theory is performed for the vortex state in two-component superconductors, such as PrOs_4_Sb_12_. We investigate the flux flow and the pinning of the vortex sheet structure. We…
Placing a high-Tc superconductor in an increasing external magnetic field, the flux first penetrates the sample through an Abrikosov vortex lattice, and then a first order transition is observed by which the system goes to the normal phase.…
We present simulations, without electrodynamical assumptions, of $B(x,y,H(t)), M(H(t))$, and $J_c(H(t))$, in hard superconductors, for a variety of twin-boundary pinning potential parameters, and for a range of values of the density and…
Using a linear analysis, we study the stability of giant-vortex states in very thin disks. The vortex expulsion and penetration fields are obtained for finite thickness disks from a numerical solution of the non-linear Ginzburg-Landau (GL)…
We examine vortex pinning and dynamics in thin-film superconductors interacting with square and rectangular pinning arrays for varied vortex densities including densities significantly larger than the pinning density. For both square and…
In type-II superconductors, magnetic flux penetrates in the form of quantized vortices whose dissipative motion, driven by the Lorentz force, can degrade superconductivity. Understanding vortex dynamics in both homogeneous regions and near…
The concept of the transition of type II superconductor into the Abrikosov state as the appearance of long-range phase coherence is considered. It is shown that this transition should be first order in ideal (without disorder)…
I show that recent theoretical [1,2] and experimental [3] claims about the possibility of the Berezinskii-Kosterlitz-Thouless (BKT) transition of ``fractional vortices'' in thin films of MgB2 are inconsistent with the parameters of the…
It is shown that the temperature of the resistive transition $T_r$ of a superconducting film can be increased by a thin superconducting or normal overlayer. For instance, deposition of a highly conductive thin overlayer onto a dirty…
A glass model of vortex pinning in highly disordered thin superconducting films in magnetic fields $B \ll H_{c2}$ at low temperatures is proposed. Strong collective pinning of a vortex system realized in disordered superconductors that are…
Recently, detailed real space imaging using scanning tunneling spectroscopy of the vortex lattice in a weakly pinned a-MoGe thin film revealed that the vortex lattice melts in two steps with temperature or magnetic field, going first from a…
Strong pinning of superconducting flux quanta by a square array of 1 $\mu$m-sized ferromagnetic dots in a magnetic-vortex state was visualized by low-temperature magnetic force microscopy (LT-MFM). A direct correlation of the…