Science: Superconductors!

The startling breakthrough that could change our world

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Forcing the pressure higher than that had no effect; it was time for more wild thinking. Chu reasoned that the high pressure worked because it squashed the compound's molecular structure and that this somehow boosted its superconducting temperature. Since more pressure did no good, Chu decided to compress the molecules in a different way -- from within. He replaced the barium with strontium, which is similar chemically but has a smaller atomic structure. Sure enough, the temperature rose again, to 54 K, then stopped. So he turned to calcium, an element with even smaller atoms. This time the temperature dropped. It appeared to be a dead end.

Now Chu's team tried lanthanum, the rare-earth* component of the IBM compound. Maw-Kuen Wu, head of the team's Alabama unit and a former graduate student of Chu's, replaced the lanthanum with another rare-earth element, yttrium.

FOOTNOTE:*The so-called rare earths, a group of 17 chemical elements, are not rare at all; yttrium, for example, is thought to be more abundant than lead. These elements were mislabeled because they were first found in truly rare minerals.

The new substance showed so much promise that Chu filed a patent application on Jan. 12. That promise was soon fulfilled. At the end of the month, after subjecting their creation to a series of heat and chemical treatments, Wu and his assistants began chilling a bit of the compound, by dousing it with liquid nitrogen, and sending an electric current through it. To their amazement, the sample's resistance began to drop sharply at a towering 93 K. Recalls Wu: "We < were so excited and so nervous that our hands were shaking. At first we were suspicious that it was an error." But a few days later he and Chu duplicated the feat in Houston and even bettered it by 5 degrees.

The accomplishment of Chu and his team did nothing to dampen their competitors' enthusiasm. Indeed, the effect was just the reverse. In order to protect his patent, Chu refused to disclose the exact composition of his new material before the formal report was published in the March 2 Physical Review Letters, but other scientists thought they could easily guess its makeup and went to work.

At the University of Illinois, Physicist Donald Ginsberg raced out to buy an air mattress and an alarm clock, anticipating a spate of all-nighters. At IBM's Almaden Research Center in San Jose, scientists successfully duplicated the compound, analyzed its crystal structure and passed the information on to the company's labs in Yorktown Heights, N.Y., where their colleagues were able to make thin films of the substance literally overnight. At the University of California, Berkeley, a group that included Theoretical Physicist Marvin Cohen, who had been among those predicting superconductivity in the oxides two decades ago, reproduced the 98 K record, then started trying to beat it. "I'm a standard American scientist," says Cohen. "My definition of research is to discover the secrets of nature -- before anyone else."

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