Solving problems at a frigid ­243 degrees Fahrenheit

By John S. Cole

Think of them as cooks of a sort ­ master chefs working to perfect an old recipe.

Each day, materials scientists at FSU's National High Magnetic Field Laboratory experiment with various ingredients in an effort to improve their products ­ superconductors, semiconductors and powerful resistive magnets.

A pinch of this element, a sprinkle of that alloy, a dab of this property and voilá!

Though oversimplified, that is the basic formula scientists around the world have been using for the past 10 years to find the materials best suited for use as high-temperature superconductors.

"It's almost like a game you play with the periodic table," said Dr. William Moulton, director of FSU's Center for Materials Research and Technology. "'If you put in a pinch of this, what do you get?'"

With every try scientists are hoping to get a more efficient material, be it a superconductor, a semiconductor or a resistive magnet, but much of the world's current focus is on the "high-temperature" superconductors.

Superconductors are special materials that, at certain low temperatures, offer absolutely no resistance to electricity. If harnessed, such materials could be used to transport electricity over long distances at low cost with little pollution.

Other potential applications include lap-top computers with power equal to that of today's mainframe supercomputers, affordable magnetic resonance imaging equipment, used by hospitals to scan soft human tissue, miniature telephone exchanges in which a million switches use but one watt of electricity ­ and the list goes on.

The most touted potential application is the "anti-gravity train," which could carry passengers on a cushion of air at more than 300 mph, running silently, without exhaust. Some scientists speculate that cars, even ships, could zip along one day using the same technology.

There's only one problem.

For a superconductor to work, it has to be super-cooled. The original "low-temperature" superconductors, discovered by physicists about 50 years ago, required temperatures near absolute 0 on the Kelvin scale (-460 degrees Fahrenheit, -273 degrees Celsius). Today's most advanced "high-temperature" superconductors operate at a relatively balmy 120 degrees Kelvin (-243 Fahrenheit, -153 Celsius). Keeping anything that cold for any length of time takes lots of energy and money.

The ultimate goal, then, is to find a material that superconducts at room temperature or higher, Moulton said.

But that's not all.

Any superconductor worth its salt has to prove its mettle by retaining its potency when exposed to certain magnetic fields. That is particularly important in the magnetic resonance imaging systems mentioned earlier. Such systems operate in a magnetic field several thousand times stronger than the earth's magnetic field. In addition, Moulton explained, higher magnetic fields could accommodate more electric current.

Using the Maglab's magnets, scientists at FSU have been able to test their materials at some of the world's highest possible magnetic fields. This ability, bolstered by FSU's capabilities with nuclear magnetic resonance, has made FSU a leader in new materials research.

Using nuclear magnetic resonance, scientists can look beyond the surface of the material and see what happens on the atomic level. That is crucial since the behavior of electrons dictates whether a substance will be a superconductor or a plain, ordinary resistive conductor, like the ones already in use.

At FSU, the information gathered through NMR experiments is shared with theorists and the scientists responsible for actually making the materials.

"The amount of talking and flowing back and forth of ideas is higher here than anywhere else in the country," said NMR experimentalist Philip Kuhns.

That, he said, is what keeps FSU on top.

"NMR research can be a self-sufficient operation, as can (theory) as can (materials production)," Kuhns said. "But to really make them fly you hook them all together."

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