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Resistance Movement : Breakthroughs in Electrical Superconductors Have Scientists Charged Up

April 05, 1987|JANNY SCOTT | Times Staff Writer

"A lot of us were--what's the proper word?--desensitized to these kinds of reports," recalled Maple. "Because (over the years) we'd seen a series of things that could not be verified or reproduced."

But a group at the University of Tokyo quickly followed up with experiments that seemed to confirm the Swiss findings. Then researchers at the University of Houston applied pressure to the new material and raised the transition temperature even further.

By early this year, labs across the United States had become involved, including labs at UCSD and Stanford that had worked with superconductivity for years. In addition to the work in Japan, reports were filtering out of China.

Opening the Door

"I mean, if it was really true, then obviously it was very important," Maple said. "And it's the sort of thing you almost couldn't not work on. You just had to. Because you know, who knows where it's going to go? We still don't know how far it's going to go."

In February, researchers in Houston and Alabama announced evidence of superconductivity at 90 Kelvins in a compound of yttrium, barium, copper and oxygen. They had broken into "liquid nitrogen temperatures," opening the door for the first time to widespread applications.

Since then, a number of labs, including Maple's, have pushed the ceiling further to 97 or 100. And late last month, physicists at Wayne State University announced they had seen evidence of superconductivity at 240 Kelvins, or 27 degrees below zero Fahrenheit.

"It's sort of put a new perspective on what 'recently' means," mused Maple. "Recently used to mean, at least to me, six months ago or last year or a year and a half ago. Now it means three days ago."

Last month in New York City, Maple convened a remarkable special session on the new developments at the annual meeting of the American Physical Society's condensed matter division, of which he is chairman. Pulled together at the last minute, the session drew an unprecedented 3,800 scientists, many of whom stayed up all night in what has been dubbed "the Woodstock of physics."

As late as November, when Maple and others were planning the annual meeting, no papers had been submitted on on the subject. But in December and January, as labs began reporting their findings, it was decided to convene the special session.

Calls began pouring in with requests to present papers. There would have been no way to decide quickly which ones to accept. So Maple and the other organizers settled on allowing just five minutes for every person who chose to speak.

"And so, time passed and we would get more and more of these calls," Maple said. "So we'd add more and more people to the program. Then we got really scared, because it was growing by leaps and bounds."

The meeting was set for the New York Hilton. Unfortunately, the grand ballroom was reserved for something else. The largest room Maple could get held 1,000, so the organizers arranged for video cameras in the rear, in the halls, and in the anteroom.

The night of the meeting, the entire area was packed.

"We were very worried because it was just a mass of people in there, and this is also a very competitive and emotionally charged subject," Maple said. "So we kind of wondered whether we could keep this under control."

The program began at 7:30 p.m. Presentations were held to 5 minutes each, with 10-minute discussion periods interspersed. The program wrapped up at 3:15 a.m., with several hundred people left. Many stayed up past dawn, talking.

"Some people say, 'Well, maybe it's like (the discovery of) the transistor,' " Maple said. "But I think not, in the sense that the transistor really opened up things that weren't even envisaged at the time. Here, the applications of superconductivity are well known. But it's something that is not generally known to the public, for some reason that I don't quite understand."

One of the more significant applications of superconductivity is in producing large magnetic fields, because the other basic property of a superconductor is that it expels from its interior a magnetic field.

Such fields can be used in laboratory research, mineral separation and in magnetic resonance imaging. Other applications include controlling the trajectory of charged particles in high-energy accelerators in controlled nuclear fusion for production of energy.

Another potential application is energy storage in superconducting solenoids, in which a wire is wound around a form like a cylinder. A current can be sent into the wire, the two ends of the wire attached, and the energy stored indefinitely with no loss.

Finally, there is talk of superconducting motors and generators in which superconducting wires replace ordinary wires. Because they would be lighter and more efficient than conventional versions, Maple said the Navy has expressed interest in using them on ships.

For the time being, the new materials capable of superconductivity are brittle ceramics that will have to be made into flexible wires before they can be used widely. Maple said they also must be improved to allow transmission of stronger currents.

But Maple, for one, is cautiously optimistic.

"This could be the very beginning," he said. "That's what's so incredible about it."

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