Science: Superconductors!

The startling breakthrough that could change our world

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Take the transmission of electricity, for example. As much as 20% of the energy sent through high-tension lines is now lost in the form of heat generated as the current encounters resistance in the copper wire. If the electricity could be sent through superconducting cable, however, not a kilowatt-second of energy would be lost, thus saving the utilities, and presumably consumers, billions of dollars. Furthermore, at least in theory, all of a large city's electrical energy needs could be supplied through a handful of underground cables.

Elimination of heat caused by electrical resistance could have a profound effect on the design and performance of computers. In their efforts to produce smaller and faster computers, designers try to cram more and more circuits into chips and ever more chips into a tiny space. But they are limited in their scaling-down endeavors by heat; even the tiny currents in computer circuits generate enough cumulative heat to damage components if they are too tightly packed. Today's personal computers could not operate without vents or internal fans to dissipate the heat. Now, with practical superconducting circuitry on the horizon, computer designers may soon see the way clear for even more remarkable miniaturization.

In still other applications, the intense magnetic fields that might someday be generated by the new superconductors should benefit any device that now uses electromagnetism in its operation -- medical diagnostic imaging machines, magnetically levitated trains, fusion-energy generators -- and will undoubtedly spawn a host of new machines. Electric motors could increase in power and shrink in size.

But these are just the most obvious examples. Scientists like Robert Schrieffer, who shared the 1972 Nobel Prize in Physics for the first successful theory of how superconductivity works, believe its most dramatic applications have yet to be conceived. "When transistors were first invented, we knew they'd replace tubes," Schrieffer says. "But no one had any idea there would someday be large-scale integrated circuits." Robert Cava of Bell Labs agrees. "We don't know where this will lead," he says. "It's exciting -- and I guess frightening at the same time."

From the time that Dutch Physicist Heike Kamerlingh Onnes discovered superconductivity in 1911 until the recent rash of breakthroughs, there was only one way to produce the phenomenon: by bathing the appropriate metals -- and later, certain metallic alloys -- in liquid helium. This exotic substance is produced by lowering the temperature of rare and costly helium gas to 4.2 K (-452 degrees F), at which point it liquefies. But the process is expensive and requires considerable energy. Furthermore, unless the liquid helium is tightly sealed in a heavily insulated container, it quickly warms and vaporizes away. Thus the practical use of superconductors has been limited to a few devices -- an experimental Japanese magnetically levitated train, a few giant particle accelerators and medicine's magnetic-resonance imaging machines -- that operate with intense magnetic fields.

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