Driven vortices in confined geometry: the Corbino disk

The fabrication of artificial pinning structures allows a new generation of experiments which can probe the properties of vortex arrays by forcing them to flow in confined geometries. We discuss the theoretical analysis of such experiments in both flux liquids and flux solids, focusing on the Corbino disk geometry. In the liquid, these experiments can probe the critical behavior near a continuous liquid-glass transition. In the solid, they probe directly the onset of plasticity.Comment: 4 pages, 2 figures, Invited talk presented at M2S-HTSC-VI, Houston, February 200

A hydrodynamic approach to the Bose-Glass transition

Nonlinear hydrodynamics is used to evaluate disorder-induced corrections to the vortex liquid tilt modulus for finite screening length and arbitrary disorder geometry. Explicit results for aligned columnar defects yield a criterion for locating the Bose glass transition line at all fields.Comment: 8 pages, 2 figures. Contributed talk at the First ESF-Vortex Matter Conference in Agia Pelagia, Crete, September 199

Vortex Physics in Confined Geometries

Patterned irradiation of cuprate superconductors with columnar defects allows a new generation of experiments which can probe the properties of vortex liquids by forcing them to flow in confined geometries. Such experiments can be used to distinguish experimentally between continuous disorder-driven glass transitions of vortex matter, such as the vortex glass or the Bose glass transition, and nonequilibrium polymer-like glass transitions driven by interaction and entanglement. For continuous glass transitions, an analysis of such experiments that combines an inhomogeneous scaling theory with the hydrodynamic description of viscous flow of vortex liquids can be used to infer the critical behavior. After generalizing vortex hydrodynamics to incorporate currents and field gradients both longitudinal and transverse to the applied field, the critical exponents for all six vortex liquid viscosities are obtained. In particular, the shear viscosity is predicted to diverge as $|T-T_{BG}|^{-\nu z}$ at the Bose glass transition, with $\nu\simeq 1$ and $z\simeq 4.6$ the dynamical critical exponent. The scaling behavior of the ac resistivity is also derived. As concrete examples of flux flow in confined geometries, flow in a channel and in the Corbino disk geometry are discussed in detail. Finally, the implications of scaling for the hydrodynamic description of transport in the dc flux transformer geometry are discussed.Comment: 27 pages, 9 figures, submitted to Physica