Vortex lattice dynamics in a-NbGe detected by mode-locking experiments

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 $V\propto f\sqrt{B}$ with $f$ the rf-frequency and $B$ the magnetic field. For large dc-velocity (corresponding to a large ML frequency), the ML current step width exhibits a squared Bessel function dependence on the rf-amplitude as predicted for ML of a lattice moving elastically through a random potential.Comment: 2 pages, 2 figures. Contribution to M2S-HTSC Ri

Transport properties of vortices in easy flow channels: A Frenkel-Kontorova study

Quantum Matter and Optic

Magnetization Decay due to Vortex Phase Boundary Motion in BSCCO

We identify a new regime of decay of the irreversible magnetization in clean Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8}$ crystals, at induction values close to the ``second peak field'' at which the bulk critical current density steeply increases. A time window is identified during which the decay of the induction is controlled by the slow propagation of the phase transformation front across the sample.Comment: 2 pages, 3 figures Paper submitted to the conference proceedings of M2S-2000 Houston T

Magnetic relaxation in the "Bragg-glass" phase in BSCCO

Magnetic relaxation in the Bragg-glass phase of overdoped Bi_2Sr_2CaCu_2O_8 crystals was investigated using time-resolved magneto-optical visualisation of the flux distribution. This has permitted us to extract the current-voltage characteristic, which can be well described by a power-law, although fits to a stretched exponential E \sim \exp(- j_{c} / j)^{\mu} with 0.3 < \mu < 0.8 are possible at long times in excess of 100 s.Comment: 2 pages, 3 figures submitted to conference proceedings of M2S-2000 Houston T

Elastic deformations in field-cooled vortex lattices in NbSe2

Quantum Matter and Optic

Vortex lattice melting in multilayers with variable anisotropies

Quantum Matter and Optic

Vortex-lattice transition in superconducting Nb/NbZr multilayers

Quantum Matter and Optic