Superconductors ready to ramp up for the real world
The Energizer bunny has nothing on Heike Kamerlingh Onnes. Nearly a century ago, the Dutch physicist stunned the scientific world when he discovered that if he chilled certain metals to extremely low temperatures, electricity raced through them without losing any energy.Skip to next paragraph
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There was just one catch: The metals had to be frozen to such frigid temperatures that the technology made no commercial sense.
More recent discoveries led to some niche applications. But today, researchers are on the cusp of applying that laboratory curiosity to a range of civilian and military technologies. They could dramatically boost the efficiency of everything from Navy destroyers to the wires that bring electricity into homes and businesses.
Superconductors - as Onnes' discovery is known - are being tested as a way to dramatically cut the risk of widespread blackouts.
"It's going to work; it's really going to work," says an enthusiastic Robert Hawsey, director of the Oak Ridge National Laboratory's Superconductivity Technology Center. Fiber optics took 20 years to emerge from the lab to become the backbone of today's information superhighway, he notes. After nearly 20 years of development, a new generation of superconductors are about to emerge from the shadows into large-scale applications.
Superconductors have a number of properties that endear them to high-tech visionaries. They have virtually no electrical resistance. In principle, once electricity begins flowing in a superconducting loop, it can flow almost forever. They carry larger amounts of electricity than standard wires and cables with similar dimensions. So superconducting components can be far smaller than their conventional counterparts.
For example, a conventional electric motor for driving a single Navy destroyer propeller might weigh as much as 200 tons, notes Scott Littlefield, director of ship science and technology at the Office of Naval Research (ONR) in Arlington, Va. A superconducting motor, in contrast, would tip the scales at 75 tons.
And superconductors don't lose their electricity to heat. Thus a superconducting motor or computer chip is vastly more efficient than its conventional counterpart.
But there are drawbacks. Superconductors are more finicky than standard electrical components. If the current it carries or the magnetic field it encounters is too strong, a superconductor turns into a mundane conductor faster than Cinderella's coach reverted to a pumpkin.
Then, there's the problem with refrigeration. To get his superconductor to work, Onnes used liquid helium at 4 Kelvin (4 degrees C) above absolute zero - the point where molecules stop moving. By the mid-1980s, traditional superconductors had moved into niche markets. But the high cost of cooling them to liquid-helium temperatures was a stumbling block to broader applications.
Then in 1986, two researchers at IBM's labs in Zurich pulled an Onnes of their own, discovering a ceramic compound that lost its resistance to electricity at a relatively balmy 35 degrees above absolute zero.
Their work set off a frenzy of research. Within weeks, other teams announced ceramic materials that became superconductors at 94 degrees above absolute zero - warm enough that they could be cooled with less expensive liquid nitrogen.
Since then, other ceramic materials have been discovered that become superconductors at more than 130 degrees above absolute zero (white hot, relatively speaking, for the superconductor world, but still 140 degrees below water's freezing point).
But these materials presented a big challenge: How to turn the ceramic into a wire.