Superconducting strip could become an ultra-low-voltage sensor

Apr 30, 2012

Researchers studying a superconducting strip observed an intermittent motion of magnetic flux which carries vortices inside the regularly spaced weak conducting regions carved into the superconducting material. These vortices resulted in alternating static phases with zero voltage and dynamic phases, which are characterised by non-zero voltage peaks in the superconductor. This study, which is about to be published in EPJ B¹, was carried out by scientists from the Condensed Matter Theory Group of the University of Antwerp, Belgium, working in collaboration with Brazilian colleagues.

Superconductors, when subjected to sufficiently strong magnetic fields, feature vortices that carry quantized amounts of , although the natural tendency of is to expel such flux. The authors relied on the Ginzburg-Landau theory to study the dynamic of the nanometric- to millimetric-scale-width superconducting strip, which was subjected to a applied at a right angle and a current applied alongside its length.

Typically, weakly acting superconducting regions are natural impediments for the passage of electrical current. However, the authors found that they also work as efficient pathways for vortices to enter and exit the superconducting strip. The increasing magnetic field also increases the density of mutually repelling vortices, which stimulates vortex motion across the strip in the presence of an external current. At the same time, the barrier for vortex entry and exit on the strip boundaries is also dependent on the magnetic field. This interplay of magnetic-field-dependent barriers and vortex-vortex interaction results in an on/off vortex motion in increasing magnetic fields.

Due to the simple geometry of the strip, these results can be confirmed experimentally in magnetoresistance measurements. These findings could be applicable in gate devices used to control various modes of on/off states in electrical systems which operate in specific windows of temperature, applied magnetic field, current and voltage.

Explore further: Experiment with speeding ions verifies relativistic time dilation to new level of precision

More information: European Physical Journal B (EPJ B), DOI: 10.1140/epjb/e2012-30013-7

Related Stories

Stripes offer clues to superconductivity

May 17, 2010

New images of iron-based superconductors are providing telltale clues to the origin of superconductivity in a class of ceramic materials known as pnictides. The images reveal that electrons responsible for ...

Tiny superconductors withstand stronger magnetic fields

Feb 04, 2005

Ultrathin superconducting wires can withstand stronger magnetic fields than larger wires made from the same material, researchers now report. This finding may be useful for technologies that employ superconducting ...

Recommended for you

How Paramecium protozoa claw their way to the top

Sep 19, 2014

The ability to swim upwards – towards the sun and food supplies – is vital for many aquatic microorganisms. Exactly how they are able to differentiate between above and below in often murky waters is ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

Macksb
1 / 5 (1) Apr 30, 2012
Similar to the vortices that appear in superfluid helium when the superfluid is stressed. The vortices are the sink into which the "super" material (superconductor or superfluid)sloughs off the stress.