Magnetic Trains, Cheap Power Brought to You by Superwires?

April 3, 2006

It's the future that was supposed to happen a decade ago: high-speed levitating trains, ultrafast computers in every office, and plenty of cheap, clean electricity, all courtesy of superconductors.

Hailed as the breakthrough replacement for copper wiring, superconductors can transport electrical current with near-perfect efficiency.

But superconducting materials have presented several technical hurdles that have kept futuristic products from reaching the public.

One of the biggest problems is that the materials are often used in conjunction with powerful magnets, and the magnetic fields can act like brakes against free-flowing electrons.

Now researchers at the U.S. Department of Energy's Oak Ridge National Laboratory (ORNL) have found a way to stop the intrusion of magnetic fields—placing a unique configuration of nanoscale dots inside the wires.

"Since most applications [for superconductors] involve high magnetic fields, we had to look for a way to sustain the superconductive flow of electric current," said ORNL's Amit Goyal, the project leader.

This latest advance means that superconducting wires can performe well enough for use in many large-scale applications.

Nanodots

Scientists have already found one possible way to overcome the other main hurdle of bringing superconductors to market: keeping the wires cool.

Conventional superconductors work at subzero temperatures—too low to be maintained economically.

Scientists are therefore pinning their hopes on high-temperature superconductors (HTS), and ceramics seem to be today's best candidates.

Ceramics are normally insulators, but they are able to superconduct at higher temperatures than most other substances—around -200°C (-328°F), or about the same temperature as liquid nitrogen.

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