Dipole-induced vortex ratchets in superconducting films with arrays of micromagnets.

Lattice effects and current reversal in superconducting ratchets

Competition between the vortex lattice and a lattice of asymmetric artificial defects is shown to play a crucial role in ratchet experiments in superconducting films. We present a novel and collective mechanism for current reversal based on a reconfiguration of the vortex lattice. In contrast to previous models of vortex current reversal, the mechanism is based on the global response of the vor...

Vortex pinning vs superconducting wire network: origin of periodic oscillations induced by applied magnetic fields in superconducting films with arrays of nanomagnets

Hybrid magnetic arrays embedded in superconducting films are ideal systems to study the competition between different physical (such as the coherence length) and structural length scales such as are available in artificially produced structures. This interplay leads to oscillation in many magnetically dependent superconducting properties such as the critical currents, resistivity and magnetizat...

Correlation length of quasiperiodic vortex lattices.

We investigated vortex-lattice dynamics in superconducting Nb thin films with different quasiperiodic arrays of magnetic pinning centers. The mixed-state magnetoresistance exhibits minima for well-defined applied fields, related to matching effects between the vortex lattice and those arrays. The results show that critical matching can originate at a local scale. For fractal arrays, the vortex-...

Magnetic field dependence of dynamical vortex response in two-dimensional Josephson junction arrays and superconducting films

The dynamical vortex response of a two-dimensional array of the resistively shunted Josephson junctions in a perpendicular magnetic field is inferred from simulations. It is found that, as the magnetic field is increased at a fixed temperature, the response crosses over from normal to anomalous, and that this crossover can be characterized by a single dimensionless parameter. It is described ho...

Asymmetric Weak-Pinning Superconducting Channels: Vortex Ratchets