Depinning of the Bragg glass in a point disordered model superconductor.

Numerical study of random superconductors

The XY model with quenched random disorder is studied numerically at T 1⁄4 0 by a defect scaling method as a model of a disordered superconductor. In 3D we find that, in the absence of screening, a vortex glass phase exists at low T for large disorder in 3D with stiffness exponent h þ0:31 and with finite screening and in 2D this phase does not exist. For weak disorder, a superconducting phase e...

Onset of Motion and Depinning of a Bragg Glass

Phase Behavior of Type-II Superconductors with Quenched Point Pinning Disorder: A Phenomenological Proposal

A general phenomenology for phase behaviour in the mixed phase of typeII superconductors with weak point pinning disorder is outlined. We propose that the “Bragg glass” phase generically transforms via two separate thermodynamic phase transitions into a disordered liquid on increasing the temperature. The first transition is into a glassy phase, topologically disordered at the largest length sc...

Direct observation of the flux-line vortex glass phase in a type II superconductor.

The order of the vortex state in La1.9Sr0.1CuO4 is probed using muon-spin rotation and small-angle neutron scattering. A transition from a Bragg glass to a vortex glass is observed, where the latter is composed of disordered vortex lines. In the vicinity of the transition the microscopic behavior reflects a delicate interplay of thermally induced and pinning-induced disorder.

Vortex glass transition in a frustrated 3D XY model with disorder.

The anisotropic frustrated three-dimensional (3D) XY model with disorder in the coupling constants is simulated as a model of a point disordered superconductor in an applied magnetic field. A finite size scaling analysis of the helicity modulus gives strong evidence for a finite temperature transition with isotropic scaling and the correlation length exponent nu=1.5+/-0.3, consistent with 3D ga...