Frenzied Hunt for the Right Stuff

By John Greenwald

Ronald Reagan positively beamed before the audience of 1,400 scientists and businessmen at the Washington Hilton Hotel last week. Declaring that the "sky is the limit," the President pledged unprecedented federal support for private U.S. efforts to develop a suddenly glamorous new breed of materials: superconducting ceramics. The substances can convey electric currents with no loss of energy at temperatures much higher than conventional superconductors. They open the way for such marvels as levitating high-speed trains and tiny but immensely powerful computers. "The breakthroughs in superconductivity bring us to the threshold of a new age," Reagan said. "It's our task to herald in that new age with a rush."

The two-day session was an all-American jamboree that pointedly excluded foreign participants. Explained William Graham, the President's science adviser: "It is not so much a fear as a certain realization. The Japanese will move very aggressively in this area." Reagan outlined an eleven-point plan that ranged from the promise of $150 million in Defense Department funds over the next three years to the relaxation of antitrust laws so that firms may collaborate on projects. Recalling remarks by Frank Press, president of the National Academy of Sciences, Energy Secretary John Herrington declared, "Superconductivity has become the test case of whether the U.S. has a technological future."

American scientists have eagerly pursued that future since last winter, when a burst of research activity rescued superconductors from relative obscurity. The excitement followed a discovery in the spring of 1986 by IBM scientists in Zurich. Their find: a metallic ceramic compound that became a superconductor at a temperature well above the previously achieved record of 23.2 Kelvin, or -418 degrees F. By year's end researchers were developing materials that became superconductors at higher and higher temperatures. At the University of Houston, a team led by Paul C.W. Chu set the currently recognized standard last February, when it produced superconductivity at a balmy 98 K (-283 degrees F).

All at once a dazzling array of superconductor uses seemed tantalizingly possible. Researchers now estimate that high-speed computers using superconductors may be three to five years away. Farther off are 300-m.p.h. trains that float on magnetic cushions, which now exist as prototypes but may take at least a decade to perfect. Power lines that can meet a city's electric needs with superconductor cables may be even farther in the future.,

But getting superconductors from the laboratory to the marketplace will be no easy task. "What worries me is that people may come to think that they're going to buy superconducting circular saws at Sears next year," says Don Capone, a physicist at Argonne National Laboratory near Chicago. Concurs Nobel Laureate Robert Schrieffer, who shared the 1972 prize for developing a theory of how superconductors work: "It's time for everyone to catch their breath and try to understand what Mother Nature has presented us."

What she has offered so far is little more than a series of challenges. While the new superconductors are easily made, their quality is often uneven. Some tend to crumble when produced in batches of more than a few ounces. Others lose their superconductivity within minutes or hours. All are brittle and extremely difficult to fabricate into wires. Scientists, moreover, lack a full understanding of how the ceramics become superconductors. That makes developing new substances largely a hit-or-miss process. "It's quite similar to when Edison was trying many different materials for light-bulb filaments," says Paul Grant, manager of magnetism and collective phenomena at IBM's Almaden Research Center in San Jose.

< Yet scientists continue to make steady breakthroughs. Among the most notable: a micron-thin film that IBM researchers developed in May to transmit useful amounts of electrical current without losing superconductivity. "That's when we all knew this thing was going to go," says Iowa State Physicist Douglas Finnemore. The film could be used in the microscopic circuitry of advanced computers. Scientists at Stanford University are refining two prototypes that could eventually become high-speed pathways between computer chips.

No research is more active or controversial than the rush to raise the temperatures at which materials become superconductors. The effort is crucial because the cost of superconductivity drops as temperature rises. While some scientists have found fleeting traces of superconductivity at room temperatures and higher, most researchers remain skeptical. Still, sober-sided scientists are on the lookout for breakthroughs. Says IBM's Grant: "The last eight months have removed the fetters from people's minds about just how high transition temperatures can go."

Researchers believe that any proof of superconductivity must include both a total absence of resistance to current and the phenomenon known as the Meissner effect. Defined as the exclusion of a neighboring magnetic field, the Meissner effect can be demonstrated by the ability of a superconductor to suspend a magnet in midair. "If you can float a magnet on the material," says Alex Zettl, a University of California, Berkeley, physicist, "there's not a scientist in the world that would not agree it's a superconductor."

Nonetheless, even substances that appear to pass both tests become suspect under closer investigation. The University of Houston's Chu recently reported that a fragment of one sample seemed to exhibit both the Meissner effect and no resistance to current at about 225 K, or -54 degrees F. Superconductivity vanished, though, when researchers repeatedly warmed and cooled the ceramic. Zettl's team had similar problems when a substance showed an indication of superconductivity at 66 degrees F, only to lose it entirely when it was heated further. Says he: "Ever since then we've been trying to reproduce the exact material. But it's like baking a cake -- no two are alike, even when you follow the exact same recipe."

So far, researchers have been unable to reproduce the dramatic results at high temperatures. Their frustrations are likely to continue while theorists hunt for a fuller explanation of how superconductivity is produced in the new materials. Already, the long-held theory about superconductivity seems to break down at current experimental temperatures. "There are at least 50 competing theories," says Frank Fradin, associate laboratory director for physical science at Argonne. Until a proven theory emerges, engineers will be a little like explorers without compasses or maps.

Meanwhile, scientists around the world are rushing to turn the new materials into useful products. In Japan, Kawasaki Steel Corp. has produced a flexible superconducting wire that equals those made in the U.S. Scientists at Nippon Telegraph and Telephone Corp. have coursed a record current through a superconductor at a temperature of 84 K. The practical-minded Japanese are optimistic about superconductors. In a survey of 21 leading Japanese researchers, most foresaw commercial superconductor applications, such as computer chips, within three years.

U.S. officials have little doubt that Japan is their primary overseas rival. Yet many superconductor researchers sharply disagree with the Administration's decision to close last week's conference to foreign scientists. The researchers argue that other countries could retaliate by cutting off Americans from the fruits of their research. Others are worried that, over the long haul, Washington may prove to be a fickle source of funds. "Money alone won't solve our problems," says Superconductor Pioneer Chu. "The Japanese have perseverance. I hope this country can be more patient. The superconductor payoff will be great. But it will take time."

With reporting by Dick Thompson/Washington and Dennis Wyss/San Francisco