Three dimensional superconducting nano-devices have arrived

While the Euston Arch may have been controversially demolished in the 1960s during redevelopment of Euston Station, but researchers just across the road in the London Centre for Nanotechnology have succeeded in re-building their own version, albeit 100 million times smaller. Their device is not merely an impressive architectural feature though, but the pickup loop (antenna) of an incredibly sensitive magnetic field sensor - a nanoscale Superconducting Quantum Interference Device or SQUID. Nanoscale SQUIDs operating at ultra-low temperatures potentially have sensitivities approaching that required for single electron spin detection - a goal that represents a grand challenge in many areas of applied physics including spintronics, bio-magnetics, nano-electromagnetics, and spin-based quantum information processing.

Until now superconducting devices have been limited to standard two dimensional thin film fabrication techniques, but in the new work the authors have succeeded in using focussed-ion beam (FIB) induced growth of freestanding superconducting nanowires to directly-write a complete three dimensional circuit which maintains its superconducting properties. Dr Ed Romans, who led the research, said "the new technique gives us tremendous flexibility to realise superconducting devices in three dimensions, for instance allowing us to measure magnetic fields on-chip along different axes, or to bring the sensor close to and around fragile samples of interest."

This work has been published in Applied Physics Letters (E.J. Romans et al., Appl. Phys. Lett. 97, 222506 (2010)).

Journal link:

Freestanding Superconducting Pickup Loop

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