This device would be useful in superconducting circuit applications.
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Superconducting electronic components
have been developed that provide
current rectification that is tunable by
design and with an externally applied
magnetic field to the circuit component.
The superconducting material used in
the device is relatively free of pinning
sites with its critical current determined
by a geometric energy barrier to vortex
entry. The ability of the vortices to move
freely inside the device means this innovation
does not suffer from magnetic
hysteresis effects changing the state of
the superconductor.
The invention requires a superconductor
geometry with opposite edges along
the direction of current flow. In order for
the critical current asymmetry effect to
occur, the device must have different vortex
nucleation conditions at opposite
edges. Alternative embodiments producing
the necessary conditions include
edges being held at different temperatures,
at different local magnetic fields,
with different current-injection geometries,
and structural differences between
opposite edges causing changes in the
size of the geometric energy barrier. An
edge fabricated with indentations of the
order of the coherence length will significantly
lower the geometric energy barrier
to vortex entry, meaning vortex passage
across the device at lower currents
causing resistive dissipation.
The existing prototype is a two-terminal
device consisting of a thin-film superconducting strip operating at a temperature
below its superconducting
transition temperature (Tc). Opposite
ends of the strip are connected to electrical
leads made of a higher Tc superconductor.
The thin-film lithographic
process provides an easy means to alter
edge-structures, current-injection geo -
metries, and magnetic-field conditions
at the edges. The edge-field conditions
can be altered by using local field(s)
generated from dedicated higher Tc
leads or even using the device’s own
higher Tc superconducting leads.
This work was done by John E. Sadleir of
Goddard Space Flight Center. For more information,
download the Technical Support Package
(free white paper) at www.techbriefs.com/tsp
under the Semiconductors & ICs category.
GSC-15643-1
This Brief includes a Technical Support Package (TSP).
Magnetic-Field-Tunable Superconducting Rectifier (reference GSC-15643-1) is currently available for download from the TSP library.