'Vortex twisters' form in superconductor bundles

17 Jun 2002

When type-II superconductors are placed in a magnetic field, the flux linesorganize themselves into small bundles. When the current flowing throughhigh-temperature superconductors is high enough, these flux lines can move, causing an unwanted voltagedrop, a major impediment to the industrial use of thesematerials.

New images of the bundles, produced by Swiss scientists, show that the bundles can entwine into stable "vortex twisters," offering a possible way out of the fluxproblem. In the recent edition of the science journal nature David Nelson of Harvard compares this to the advent of the Iron Age, when smiths strengthened iron byadding dislocation defects through bending.