Cold logic promises speedy devices

Researchers from the University of Cambridge and Hitachi Cambridge Laboratory have made a superconducting logic circuit that computes very quickly and requires little power.

Superconducting materials allow currents of electrons to pass through without resistance; this allows transistors made of the material to work very fast. The downside is today's superconductors work only at extremely low temperatures.

The researchers' used transistors made from the superconductor niobium to construct a NOT gate, a logic circuit that reverses a bit of digital information, turning a 0 into a 1 and vice versa. The researchers fabricated the transistors using ion beams to etch a thin film of niobium, a process compatible with those used to manufacture today's transistors.

The superconducting circuits could eventually be used in highly-sensitive magnetic field sensors and as logic circuits for quantum computers. Practical superconducting transistor devices are possible within two to five years, according to the researchers.

The work appeared in the January 16, 2003 issue of the journal Nanotechnology. -TECHNOLOGY RESEARCH NEWS }Ù