Word: compounds
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Dates: during 1980-1989
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Since the Houston lab had special equipment for testing materials at high pressure, Chu wondered what would happen if he pressurized the IBM compound. "Using known theories," he says, "you don't expect the transition temperature to go up rapidly under pressure, but it shot up like a rocket. It suggested to us that there might be some new mechanism involved." That unexpected result, says Chu, played right into what he considers his group's strong suit: "We feel we have an advantage over some other groups because we are not confined to conventional thinking. We think wildly." Chu found...
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...
...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...
...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...
...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...