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We have studied the flow properties of vortices driven through easy flow mesoscopic channels by means of the mode locking (ML) technique. We observe a ML jump with large voltage broadening in the real part of the rf-impedance. Upon approaching the pure dc flow by reducing the rf amplitude, the ML jump is smeared out via a divergence of the voltage width. This indicates a large spread in internal frequencies and lack of temporal coherence in the dc-driven state.
We study the behavior of vortex matter in artificial flow channels confined by pinned vortices in the channel edges (CEs). The critical current $J_s$ is governed by the interaction with static vortices in the CEs. We study structural changes associat
We observed mode-locking (ML) of rf-dc driven vortex arrays in a superconducting weak pinning a-NbGe film. The ML voltage shows the expected scaling $Vpropto fsqrt{B}$ with $f$ the rf-frequency and $B$ the magnetic field. For large dc-velocity (corre
The flow properties of confined vortex matter driven through disordered mesoscopic channels are investigated by mode locking (ML) experiments. The observed ML effects allow to trace the evolution of both the structure and the number of confined rows
We analyze the structure of an $s-$wave superconducting gap in systems with electron-phonon attraction and electron-electron repulsion. Earlier works have found that superconductivity develops despite strong repulsion, but the gap, $Delta (omega_m)$,
We study the thermodynamics of ultrasmall metallic grains with the mean level spacing comparable or larger than the pairing correlation energy in the whole range of temperatures. A complete picture of the thermodynamics in such systems is given takin