Race to Build Better Superconductor--a Scientific Scramble
Chemist Donald Capone missed his Christmas vacation last year working overtime in his lab here, and now he has missed his Easter vacation also.
For most of the last four months, in fact, Capone has been working 12 to 16 hours a day, seven days a week, in his lab at the Argonne National Laboratory, living on junk food and engaging in an international scientific race the likes of which has not been seen in this decade.
Capone is not alone in his devotion. As many as 50 researchers here have joined in a frantic effort to beat the rest of the world to build a better superconductor.
That hard work paid off for Capone three weeks ago when he made the first measurement of the current-carrying capacity of a wire formed from the new superconducting material.
That was a small but important step in a quest that could over the next two decades lead to a revolution in the transmission of electricity, bringing with it levitating magnetic railroad trains, smaller and faster computers and more efficient long-distance power transmission. Scientists are comparing recent work on superconductivity to the discovery of nuclear fission or the development of the transistor.
No Loss of Power
Superconducting materials transmit electricity with no loss of power due to resistance. In contrast, even such good electrical conductors as silver and copper display some power loss due to resistance, often as much as 25% in long-distance transmission.
As recently as a few months ago, only a handful of scientists throughout the world were studying superconducting materials. Since December, the field has exploded with activity, not only in the United States, but also in Japan, Western Europe, China, India and the Soviet Union. This burst of research has resulted in a series of breakthroughs in the field.
Until recently, only a few metals and metal alloys displayed superconductivity, and then only at extremely low temperatures. The best superconductors now available commercially have to be cooled to minus 419 degrees Fahrenheit, or below 23.2 degrees on the Kelvin scale commonly used by scientists, before they become superconducting. This is normally achieved by bathing them in liquid helium, a process that is both very expensive and very inefficient.
As a result, the practical uses of superconductors have been limited. Superconducting metals are now used to make very powerful magnets for accelerators used by physicists and imaging devices used by physicians.
In January, 1986, however, two Swiss scientists found that a metal oxide ceramic became superconducting at a temperature of about 30 degrees Kelvin (minus 406 degrees Fahrenheit). Their findings, published in an obscure European journal last April, went nearly unnoticed until December, when Japanese scientists reported a confirmation of their finding at a scientific meeting in Boston.
The Boston meeting served to unleash hundreds of researchers in a mad race for glory and fortune.
The findings that have followed have pushed the superconducting temperature above 77 degrees Kelvin, which permits the use of liquid nitrogen as a coolant. Cooling with liquid nitrogen is much easier and much, much cheaper than cooling with liquid helium, and opens a whole new spectrum of potential uses for superconductors.
The superconductivity research at Argonne is typical of the activity going on elsewhere; it represents the scientific world in microcosm. But Argonne is the federal government’s principal site for superconductivity research.
It is also, spokesman David Baurac says, the only facility that is capable of making the new superconductors in pound quantities rather than grams, and scientists there hope to exploit this advantage before other labs develop a similar capability.
“There is a Nobel Prize lurking out there,” says Argonne director Alan Schriesheim, “and probably two--one for the person who finds the best high-temperature superconductor and one for the person who explains how it works. Maybe even a third if there is a unique societal impact we don’t see today.”
Beyond the scientific glory, furthermore, lie potentially immense riches.
Jump on the Competition
The companies or individuals who have patents on the basic superconducting materials or on devices made from it will have a significant leg up on the competition and will be in a position to reap rich rewards. Consequently, the U.S. Patent Office is being deluged with applications from anyone who has ever made a new superconducting material, and many years will pass, experts say, before all the claims of priority will be sorted out.
(Because they work for a federal laboratory, Argonne scientists do not stand to profit from their work. The federal government owns rights to their inventions.)
Scientific journals and societies are also being inundated. The journal of choice for most scientists studying superconductivity is the prestigious Physical Review Letters. Three weeks ago, the journal published an announcement that it had already received 50 papers dealing with superconductivity and expected another 150 to 200 by June.
To cope with this flood, the editors said that they had created a special panel to parcel many of the papers out to other journals published by the American Physical Society and that “requests for reconsideration of the editors’ decisions are inappropriate.”
At a recent meeting of the American Physical Society in New York City, furthermore, a special symposium on the new superconductors was scheduled at the last minute. Anyone who wanted to report results was given five minutes. More than 1,800 scientists crowded into a room meant for 1,100, and 2,000 more watched on closed-circuit television in adjacent rooms.
The session ran until 3:15 the next morning and many scientists, too excited to sleep, were still wandering the halls at dawn discussing the new findings.
A similar session will begin Thursday in Anaheim, and organizers expect it to be nearly as hectic. A symposium on superconductivity was originally scheduled to last one day, but has now been expanded to two full days and one evening.
Elements of Drama
The story of Argonne’s involvement in this race has some elements of the spy thriller. Its genesis goes back to last year when K. Alex Muller and J. Georg Bednorz of the IBM Zurich Research Laboratory in Switzerland reported that a ceramic containing lanthanum, barium, copper and oxygen showed traces of superconductivity at 30 degrees Kelvin.
“Hardly anyone saw Muller’s paper, and those who did didn’t believe it,” Argonne’s David Hinks said somewhat ruefully. Two who did believe were physicists Shoji Tanaka at the University of Tokyo and Paul C. W. Chu of the University of Houston.
Chemist Ivan Schuller of Argonne went to see a presentation at the Boston meeting by Koichi Kitizawa of Tanaka’s group. “The (presentation of Kitizawa’s) paper wasn’t on the program, and it wasn’t clear that it would be important,” said materials scientist Merwyn Brodsky of Argonne.
But it was a “solid, convincing report,” Hinks said. “The Japanese had a structure for the compound and they saw a real drop to zero resistance at 23 degrees Kelvin. Ivan was convinced it was real, and he convinced us.”
AT&T; Bell Laboratories also was convinced. They flew Kitizawa to their Murray Hill, N.J., laboratory, where he repeated the presentation.
“On Monday, Dec. 15, Ivan gave us an impromptu seminar,” Brodsky said. “Three people started making the compounds immediately, and by the end of the week we saw good results.”
Argonne normally closes for two weeks at Christmas, but most of the investigators who had any link to the superconductors canceled their plans and stayed in their labs.
The work was emotionally wrenching, Capone noted. “Sometimes you felt like you wanted to climb up on the roof and jump off” when experiments didn’t work out as planned, he added.
Wrong Step
One such time occurred over the holidays when the Argonne group tried to find new compounds by varying the composition of the ceramic. Most researchers have had success by replacing the lanthanum with other elements, but they didn’t know that then.
“We started with the wrong atom, copper,” Hinks said, “and it was a major disaster. But we only worked with it a week, so it wasn’t as bad as it could have been.”
The first new superconductor they found was superconducting at about 40 degrees Kelvin (minus 381 degrees Fahrenheit). While they were confirming their finding at the end of December, however, Robert J. Cava and his colleagues at Bell Labs publicly reported the same results.
On Friday, Feb. 13, in Houston, Chu announced the discovery of a material that became superconducting at 93 degrees Kelvin (minus 286 degrees Fahrenheit). “By Monday morning, we had made the compound and confirmed his discovery,” said Argonne’s Frank Fradin.
Since that fateful Friday, investigators at Argonne and elsewhere have found at least 13 other ceramics that are also superconducting at temperatures between 90 and 95 degrees Kelvin.
(The Kelvin scale proceeds from a temperature of absolute zero--that point at which all motion of atoms ceases.)
Meanwhile, crystallographers at Argonne have determined the structure of the material discovered by Chu. Other labs have used X-ray crystallography to determine the structure, Fradin said, but X-rays don’t reveal the locations of the oxygen atoms precisely.
Argonne scientists, however, were able to use a unique piece of equipment called an Intense Pulsed Neutron Source to analyze the structure of crystals of the superconductors, Fradin said, and to precisely locate the oxygen atoms in the crystals. Fradin hopes that information from this structure will give hints about other types of materials that might be superconducting.
Major Advancement
Richard Weeks’ group at Argonne has been producing thin films, pellets, and especially wires from the material and measuring their characteristics. Weeks believes they were the first to make thin (.006 of an inch) wires from the material, and he terms that “a very key step” toward the commercialization of the materials.
Capone thinks that Argonne’s most significant achievement so far was the demonstration that the ceramics could produce a high magnetic field, a feature that should also ensure many potential applications.
The paper describing that effect, he noted, was finished in a four-hour stint in a booth at a chain restaurant. “We were there until it closed, and we had our papers spread out all over the place,” he said. “Nobody would come near us.”
In part because no one has found anything that is superconducting at a temperature higher than 95 degrees Kelvin, the pace has slowed slightly. The Argonne researchers welcome the respite because it gives them time to consolidate their previous work and try to understand it better.
For his part, Capone now makes it a point to go home for at least an hour for supper to see his children. But he is not going to slow down much more than that.
