Superconductors!

By MICHAEL D. LEMONICK

They began lining up outside the New York Hilton's Sutton Ballroom at 5:30 in ^ the afternoon; by the time the doors opened at 6:45, recalls Physicist Randy Simon, a member of TRW's Space and Technology Group, "it was a little bit frightening. There was a surge forward, and I was in front. I walked into the room, but it wasn't under my own power." Recalls Stanford Physicist William Little: "I've never seen anything like it. Physicists are a fairly quiet lot, so to see them elbowing and fighting each other to get into the room was truly remarkable."

Thus began a session of the American Physical Society's annual meeting that was so turbulent, so emotional and so joyous that the prestigious journal Science felt compelled to describe it as a "happening." AT&T Bell Laboratories Physicist Michael Schluter went even further, calling it the "Woodstock of physics." Indeed, at times it resembled a rock concert more than a scientific conference. Three thousand physicists tried to jam themselves into less than half that number of seats set up in the ballroom; the rest either watched from outside on television monitors or, to the dismay of the local fire marshal, crowded the aisles. For nearly eight hours, until after 3 a.m., the assembled scientists listened intently to one five-minute presentation after another, often cheering the speakers enthusiastically. Many lingered until dawn, eagerly discussing what they had heard and seen.

What stirred all the excitement at that tumultuous meeting in March was a discovery that could change the world, a startling breakthrough in achieving an esoteric phenomenon long relegated to the backwaters of science: superconductivity. That discovery, most scientists believe, could lead to incredible savings in energy; trains that speed across the countryside at hundreds of miles per hour on a cushion of magnetism; practical electric cars; powerful, yet smaller computers and particle accelerators; safer reactors operating on nuclear fusion rather than fission and a host of other rewards still undreamed of. There might even be benefits for the Strategic Defense Initiative, which could draw on efficient, superconductor power sources for its space-based weapons.

Superconductivity is aptly named. It involves a remarkable transition that occurs in many metals when they are cooled to temperatures within several degrees of absolute zero, or, as scientists prefer to designate it, 0 Kelvin. Absolute zero, equivalent to -460 degrees F or -273 degrees C, represents a total absence of heat; it is the coldest temperature conceivable. As the + metals approach this frigid limit, they suddenly lose all their electrical resistance and become superconductors. This enables them to carry currents without the loss of any energy and in some cases to generate immensely powerful magnetic fields. Scientists have recognized for years that the implications of this phenomenon could be enormous, but one stubborn obstacle has stood in their way: reaching and maintaining the temperatures necessary for superconductivity in these metals is difficult and in most instances prohibitively expensive.

Now, in a series of rapid-fire discoveries, researchers around the world have begun concocting a different class of materials that become superconductors at significantly higher temperatures -- levels that, while still beyond the reach of a kitchen refrigerator, are easier and less costly to attain. These achievements have had an electrifying effect on a subject that just a year ago would have elicited yawns from physicists and blank stares from politicians. Indeed, hardly a week has passed since the New York City meeting without reports from competing scientists -- in the popular press as well as in professional journals -- of new superconducting materials and ever higher temperature ranges. An effect that once could be detected only with sophisticated equipment has become a common sideshow at conferences: a sample of one of the new materials is placed in a dish of liquid nitrogen, and a magnet placed above it. Since superconductors repel magnetic fields, a phenomenon called the Meissner effect, the magnet remains suspended in midair.

Fun and games aside, though, the competition is growing more intense. Researchers around the world are canceling vacations, ignoring their families, moving cots into their labs and subsisting on takeout food and microwave popcorn. "We've been working since right after Christmas," says Physicist J.T. Chen of Wayne State University in Detroit. "We do experiments almost every day. Sometimes we sleep only three or four hours. Maybe it was like this when the transistor was invented, but in my personal experience this is unique." Says Japanese Chemist Kohji Kishio: "The race is for the Nobel Prize."

The world's leading industrial nations are in a race of another kind. Quick to recognize the commercial potential of the new development, Japan's Ministry of International Trade and Industry plans to subsidize private-sector research, and will establish a center in Nagoya to test equipment made from * superconducting materials. In Washington, the Department of Energy has decided to double this year's research support for superconductors to $40 million; it is also compiling a computerized database that will enable American scientists to keep up to date on fast-breaking superconductor research results, and will co-sponsor a White House conference on superconductivity this summer. "It's a monumental subject," says Energy Secretary John Herrington. "It ranks up there with the laser." In the Senate, Minnesota Republican David Durenberger has co-sponsored a bill calling on the President to form a national commission to coordinate superconductivity research and development. Says Durenberger: "We cannot stand idly by while Japan targets another industry for industrial supremacy." Last week the National Science Foundation announced $1.6 million in grants to help keep the U.S. competitive in superconductivity research.

The superlatives roll in. "In terms of the societal impact, this could well be the breakthrough of the 1980s in the sense that the transistor was the breakthrough of the 1950s," says Alan Schriesheim, director of Argonne National Laboratory near Chicago. Indeed, scientists hardly know where to start in describing the bonanza that superconductors could yield.

Take the transmission of electricity, for example. As much as 20% of the energy sent through high-tension lines is now lost in the form of heat generated as the current encounters resistance in the copper wire. If the electricity could be sent through superconducting cable, however, not a kilowatt-second of energy would be lost, thus saving the utilities, and presumably consumers, billions of dollars. Furthermore, at least in theory, all of a large city's electrical energy needs could be supplied through a handful of underground cables.

Elimination of heat caused by electrical resistance could have a profound effect on the design and performance of computers. In their efforts to produce smaller and faster computers, designers try to cram more and more circuits into chips and ever more chips into a tiny space. But they are limited in their scaling-down endeavors by heat; even the tiny currents in computer circuits generate enough cumulative heat to damage components if they are too tightly packed. Today's personal computers could not operate without vents or internal fans to dissipate the heat. Now, with practical superconducting circuitry on the horizon, computer designers may soon see the way clear for even more remarkable miniaturization.

In still other applications, the intense magnetic fields that might someday be generated by the new superconductors should benefit any device that now uses electromagnetism in its operation -- medical diagnostic imaging machines, magnetically levitated trains, fusion-energy generators -- and will undoubtedly spawn a host of new machines. Electric motors could increase in power and shrink in size.

But these are just the most obvious examples. Scientists like Robert Schrieffer, who shared the 1972 Nobel Prize in Physics for the first successful theory of how superconductivity works, believe its most dramatic applications have yet to be conceived. "When transistors were first invented, we knew they'd replace tubes," Schrieffer says. "But no one had any idea there would someday be large-scale integrated circuits." Robert Cava of Bell Labs agrees. "We don't know where this will lead," he says. "It's exciting -- and I guess frightening at the same time."

From the time that Dutch Physicist Heike Kamerlingh Onnes discovered superconductivity in 1911 until the recent rash of breakthroughs, there was only one way to produce the phenomenon: by bathing the appropriate metals -- and later, certain metallic alloys -- in liquid helium. This exotic substance is produced by lowering the temperature of rare and costly helium gas to 4.2 K (-452 degrees F), at which point it liquefies. But the process is expensive and requires considerable energy. Furthermore, unless the liquid helium is tightly sealed in a heavily insulated container, it quickly warms and vaporizes away. Thus the practical use of superconductors has been limited to a few devices -- an experimental Japanese magnetically levitated train, a few giant particle accelerators and medicine's magnetic-resonance imaging machines -- that operate with intense magnetic fields.

But in the past year and a half physicists have stumbled on an unusual class of ceramic compounds that change everything. They too must be cooled to become superconductors, but only to a temperature of 98 K (-283 degrees F). And that suddenly brings superconductivity into the range of the practical; liquid helium can be replaced as a coolant by liquid nitrogen, which makes the transition from a gas at the easily produced temperature of 77 K (-320 degrees F). Moreover, liquid nitrogen is cheaper by the quart than milk and so long- lasting that scientists carry it around in ordinary thermos bottles. Also, the & ceramics may be able to generate even more intense magnetic fields than metallic superconductors. Thus, if these new substances can be turned into practical devices -- and most scientists believe they can -- technology will be transformed. Declares Arno Penzias, vice president for research at Bell Labs: "The recent advances in the field of superconductivity are almost without comparison."

Success and celebrity have been a long time in coming to the field of superconductivity. "Until recently," says John Ketterson, a physicist at Northwestern University, "people were glum. There hadn't been a breakthrough in a long time. Funding was drying up. This has sent everyone back into the field with a new burst of enthusiasm." Although Kamerlingh Onnes envisioned early on that his discovery might pave the way for extremely powerful, compact electromagnets, he and other experimenters were stymied by a strange phenomenon: as soon as enough current was flowing through the then known superconductors (lead, tin and mercury, among others) to generate significant magnetic fields, the metals lost their superconductivity.

It was not until the 1950s that scientists discovered alloys, such as niobium tin and niobium titanium, that keep their superconductivity in the presence of intensely strong magnetic fields. And it was not until the '60s and '70s that the manufacture of large superconducting magnets became standardized. But progress toward the other goal of superconductivity researchers, pushing the phenomenon into a practical temperature range, was even slower. By 1973, some 62 years after Kamerlingh Onnes had found superconductivity in mercury at 4.2 K, scientists had upped the temperature to only 23 K, using an alloy of niobium and germanium. After 1973: no improvement.

That was the situation in 1983 when Karl Alex Muller, a physicist at the IBM Zurich Research Laboratory in Switzerland, decided to pursue an approach to superconductivity that had met with limited success in the past. Instead of using the kind of metallic alloys that held the existing record, he turned his attention to the metallic oxides (compounds of metals and oxygen) known as ceramics. Some theorists had suggested ceramics as potential superconductors even though they were poor conductors at room temperatures. In fact, ceramics are often used as insulators-for example, on high-voltage electric- transmission lines.

Muller and his colleague, Johannes Georg Bednorz, tinkered with hundreds of different oxide compounds over the next few years, varying quantities and ingredients like alchemists in search of the philosopher's stone. Finally, in December 1985, they came across a compound of barium, lanthanum, copper and oxygen that seemed promising. When Bednorz tested the compound, he was startled to see signs of super-conductivity at an unprecedented 35 K, by far the highest temperature at which anyone had observed the phenomenon. Could this result be correct? Aware of some hastily made superconductivity claims that later could not be reproduced, the IBM team proceeded cautiously, painstakingly repeating their experiments. In April 1986, Muller and Bednorz finally submitted the findings to the German journal Zeitschrift fur Physik, which published it five months later.

As Muller had anticipated, other physicists were skeptical. For one thing, the IBM scientists had lacked the sensitive equipment to test for the Meissner effect, the surest proof of superconductivity, and thus could not confirm it in their report. More important, in a field where improvements of a few degrees were reason for celebration, this great a temperature leap seemed unlikely. Douglas Finnemore, a physicist at Iowa State University, admits that he was among the doubters. "Our group read the paper," he says. "We held a meeting and decided there was nothing to it."

Not everyone was so quick to dismiss the discovery. Scientists from the University of Tokyo took a look at the substance. Says Muller: "The Japanese weren't smiling, and they confirmed it. Then the United States sat up." By the end of the year, confirmation had come from China and the U.S., and suddenly a nearly moribund branch of physics was the hottest thing around. Large industrial and government laboratories jumped in; so did major universities. At Bell Labs, a team led by Bertram Batlogg and Ceramist Cava had launched their own program of alchemical tinkering. Soon they had manufactured a similar compound that became a superconductor at 38 K, one- upping their archrivals at IBM. "That's when the hysteria started," says Cava. "The place was abuzz with excitement."

But Bell Labs too was soon to be upstaged. For among those who had given early credence to the news from Zurich was a small, modestly equipped team of researchers headed by Paul C.W. Chu of the University of Houston. Chu had been studying superconductivity since 1965; now he and his group, including scientists from the University of Alabama, quickly reproduced the IBM results and moved on to their own experiments.

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 that the compound remained a superconductor up to 52 K (-366 degrees F) when subjected to from 10,000 to 12,000 times normal atmospheric pressure.

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."

In short, says Douglas Scalapino, of the University of California at Santa Barbara, recent developments are something like the breaking of the four- minute mile. Beforehand, it had been considered nearly impossible; afterward, "you could go to any track meet and some guy was breaking it." The activity, says Cava, "is more exciting than a supernova. Astrophysicists can watch it, but when it happens, it happens and it's gone. In superconductivity, the events are still going on, and the physics is just beginning to pour in."

So are the scientific papers. Says Metallurgist Frank Fradin, director of Argonne's materials science division, who is also an associate editor of Physical Review Letters: "As of three weeks ago, we had 98 papers submitted on the subject, and only a small fraction of them will ever get published. Progress is so rapid that a result of two to three weeks ago is already out of date. We've had to institute a whole new system to speed up the publication process." One important discovery: at least a dozen different compounds, all subtly different from the one Chu found, appear to act as high-temperature superconductors.

While scientists know the chemical composition of the new class of superconductors, they are less certain about how they work. True, a theory exists that explains low-temperature superconductivity. It is known as BCS, from the initials of Author John Bardeen and his colleagues Leon Cooper and Robert Schrieffer, who shared the 1972 Nobel Prize for Physics for their effort. But BCS may not apply to the strange goings-on at higher temperatures.

Ordinary conductivity, the measure of a material's ability to transmit electrical current, is determined by events that take place at the atomic level. Atoms consist of a tiny dense nucleus that contains positively charged protons and chargeless neutrons. Around the nucleus whirl the negatively charged electrons, residing in shells with shapes determined by the electrons' energy levels.

In many atoms, particularly those of metallic conductors, the outer shell has a number of empty slots, and the electrons that it does contain are not bound as tightly to it as those in the inner shells. Just as the sun's gravitational pull is weaker on distant Pluto than on nearby Mercury, the hold of an atomic nucleus is also weaker on electrons in the outermost layers.

So when an electric current -- which is simply a stream of moving electrons -- flows in a conductor, electrons move from empty slot to empty slot in the outer shells of the atoms. A material like rubber, on the other hand, is an insulator: it consists largely of atoms with completely filled, stable outer shells. Thus when voltage is applied, electrons have no empty slots to move into, and no current flows.

But even the best of ordinary conductors have some resistance to the flow of electrical current. The reason: as current passes through, some of the electrons collide with other electrons, thus dissipating their energy in the form of heat. According to the BCS theory, these collisions are avoided in superconductivity. "What causes a material to become superconducting is a phase change,"* explains Bardeen, now a professor emeritus at the University of Illinois. "You can think of it as electrons condensing into a new state." That state involves the pairing of electrons and a kind of group discipline.

FOOTNOTE:*The most familiar example of a phase change is the transformation, at 32 degrees F, of water from a fluid into crystalline ice.

Iowa's Finnemore compares the movement of the electrons in a superconductor to a crowd moving across a football field. "If they act as individual particles," he explains, "they will bump into each other and scatter. That's the equivalent of electrical resistance. But suppose someone starts counting cadence, and everyone locks arms and marches in step. Then even if one person falls into a chuckhole, he won't fall because his neighbors hold him up." Thus in a superconductor electrons move unhindered.

While the BCS theory works well near absolute zero, some physicists think it will have to be modified or even scrapped as an explanation for the behavior of higher-temperature superconductors. According to Bardeen, his theory can explain superconductivity up to around 40 K. But at 90 K, he says, "I think it's highly unlikely. We no doubt are going to need a new mechanism." In fact, says Schrieffer, "superconductivity may turn out to have as many causes as the common cold."

Confusion at the level of theory has put no damper on the orgy of speculation about potential applications. Some ideas involve upgrading existing superconducting technology; others push marginal technology into the realm of the profitable; still others raise the prospect of entirely new uses of the phenomenon.

Giant particle accelerators are one target for possible upgrading. Currently the most powerful such devices use conventional superconducting electromagnets. If high-temperature superconducting magnets can be developed, millions of dollars could annually be saved in electrical and liquid-helium bills.

Electromagnets are also crucial to fusion energy, which depends on fusing atoms (the same process that powers the sun), rather than splitting them. Key to one promising fusion process, which is under development in several countries, is a "bottle" composed not of any material substance but of powerful magnetic fields, generated at great expense by conventional electromagnets. Such fields are the only envelopes that can contain and squeeze atoms together at the hundred-million-degree temperature required to initiate fusion. But superconducting magnets, especially warm-temperature ones, could produce more intense fields at less expense and thus could "help make fusion power possible and practical," says Harold Furth, director of Princeton University's Plasma Physics Laboratory.

In medicine, superconducting magnets are at the heart of magnetic resonance- imaging machines. The magnets' powerful fields first align the atoms of the body. Then a pulse of radio waves knocks them momentarily out of alignment. When the atoms return to their previous attitudes, they emit radiation that produces detailed images of the body's soft tissues. MRI machines in use today are enormous (6 ft. by 8 ft. by 10 ft.), largely because of the more than $100,000 worth of bulky insulation required to preserve the liquid helium coolant, which costs an additional $30,000 annually. The improved economics of the new superconductors, says Walter Robb, of General Electric's Research and Development Center, should eventually enable medical institutions to install many more MRI machines, which are invaluable for diagnosing disorders like brain tumors.

High-temperature superconducting magnets may become important in the maglev, or magnetically levitated, trains under development in Japan and West Germany. And scientists at Japan's Mercantile Marine University in Kobe have already developed a working scale model of a ship with a propulsion system based on magnetism. Physicist Yoshiro Saji sends current through the seawater from an onboard electric generator via ship-bottom electrodes. A superconducting magnet, also on board, creates a strong magnetic field. As the electromagnetic field produced by the electric current pushes against the field of the magnet, the ship moves forward. Saji has already moved up his timetable and hopes to complete a 100-ton "magship" within four years. "Thanks to the new materials," he says, "magnets will be lighter and easier to handle. Once we can replace liquid helium with liquid nitrogen, the whole process of outfitting the ship will be simplified. It's a fantastic development."

On a smaller scale, superconductors have already been used to create superfast electronic switches called Josephson junctions (after Nobel Laureate Brian Josephson, the British physicist who discovered the principle on which they are based), which until now could operate only at liquid-helium temperatures. For both technical and economic reasons, IBM abandoned its Josephson junction project in 1983. But IBM Physicist Sadeg Faris quit the company, obtained licenses for the technology and formed Hypres, Inc., which has begun marketing its first Josephson junction product -- a high-speed oscilloscope. Says Faris: "The new materials are at a primitive stage, but we're anxious to exploit them to bring down costs and improve speed." Since switches are a limiting factor in computer speed, an economical Josephson junction could prove invaluable.

At Westinghouse, scientists are working on the idea of using superconductors for electric-power production. Today's nonsuperconducting generators produce electricity by spinning wire-wrapped rotors in a magnetic field; their output is typically some 300 megawatts a generator. If the field were generated even by conventional superconducting electromagnets, says Research Director John Hulm, the output could be doubled. The benefits would be even greater with high-temperature superconductors.

And then there are the daydreams: giant underground loops of superconducting cable that can store vast amounts of electricity for later use; cars that run on tiny, powerful electric motors, drawing current from superconducting storage devices. But even the daydreams are taken at least somewhat seriously. At Ford, for example, a study group has been assembled to rethink the feasibility of the electric car in light of the recent advances in superconductivity. Says IBM Physicist John Baglin: "The question is not 'How can we take this material and do something everyone has wanted to do?' but 'How can we do something that no one has yet imagined?' " Some tongue-in- cheek suggestions overheard at a superconductor meeting: superconducting ballroom floors and rinks that would enable dancers and skaters literally to float through their motions.

All the applications, though, depend on bringing the technology out of the lab, and despite the bubbly confidence of many scientists, obstacles remain. One is the need to form the new materials into usable shapes. While metals bend, anyone who has dropped a dinner plate knows that ceramics do not. And a flexible material has a big advantage over a brittle one if it is to be coiled around an electromagnet. Says Osamu Horigami, chief researcher at Toshiba's Energy Science and Technology Laboratory: "To get a magnet or coil or even a wire we could use with complete confidence could take another five years." Agrees Hulm: "It will take extraordinary engineering to solve the brittleness problem."

IBM scientists may already have a partial answer: they announced last week that the new compounds can be "spray-painted" onto complex forms, where they solidify. Says IBM Scientist Jerome Cuomo, who described the technique at the American Ceramic Society conference in Pittsburgh: "This opens the door wider than ever to the fabrication of useful objects made of superconducting materials."

More fundamental is the fact that while the new ceramics remain superconductors at high temperatures and can withstand intense magnetic fields, they can as yet carry only about a hundredth of the current capacity of conventional superconductors. And because the amount of current flowing through the magnetic field determines its strength, scientists are concerned that a quick fix may not be in sight. Warns GE's Robb: "What we need now is a second invention that would modify copper oxides to allow high currents to flow at high temperatures. There's a fifty-fifty chance that second invention will ever be made."

Finally, there is a human problem that could hinder progress in the suddenly vigorous field of superconductivity: the increasing unwillingness of scientists to exchange information about their experiments. At the Woodstock of physics meeting, for example, some were miffed when Stanford researchers, following their presentation, refused to divulge further details of their research; they had been advised by patent attorneys to reveal as little as possible until their work was legally protected. The competition extends beyond legal rights. Two weeks after Chu's record-breaking temperature was announced, the Berkeley team independently came up with the same superconducting compound. They immediately mailed a report of their results to Physics Letters, hoping it would be received before Chu's paper was published. Reason: they wanted to establish that they had not merely copied his work.

Still, there are hints that some of the physical barriers, at least, are starting to fall. At the March meeting, scientists were already showing rings and flexible tapes made of high-temperature superconductors; by the end of the month, teams at IBM, Bell Labs, Toshiba, Argonne and a handful of other places were developing wire-thin ceramic rods. Says Toshiba's Horigami: "We weren't even sure this was possible. When we finally had a wire that could potentially be coiled, there was absolutely no way to measure our sense of triumph." Argonne Ceramist Roger Poeppel now talks of building a furnace ten feet long to fire his group's wire almost continuously as it is extruded. "We think it will be flexible enough to twist into cable," he says, "and cable is the building block for magnetic coils and electrical transmission lines. With two miles of wire, we'll make a superconducting magnet. To get a practical device + is now the race."

Later, in April, scientists at Stanford and IBM announced that they had made thin films of the new substances, important for computer applications. The spotlight then shifted to IBM Researchers Robert Laibowitz and Roger Koch, who reported that they had made their own thin film into a working gadget called a SQUID (for superconducting quantum interference device). Such tools are already used in low-temperature versions to measure extremely faint magnetic fields. They are also employed by physicists in the search for elusive gravity waves and magnetic monopoles, predicted by some theories but not yet observed. Medical researchers use SQUIDs to detect the minute fields generated by electrical activity within the brain. High-temperature SQUIDs should make all these searches a little easier.

Other scientists are seeking a better understanding of why the ceramics become superconductors. Many labs have taken pictures of the materials with electron microscopes, pulsed beams of neutrons, X rays and ultrasound. A team of Bell Labs and Arizona State scientists has produced electron-microscope photographs that show defects in the compound's crystalline structure. Says Team Leader Abbas Ourmazd: "We don't quite understand what role the defects play, but it raises some provocative questions. Is it the perfect material that is superconducting? Or is it the defects? If it turns out that it is the defects, then we will want to control them and increase their density and put them in intentionally."

Most intriguing of all are reports that the temperature record set by Chu and since matched by dozens of other researchers has already been surpassed. Some physicists have even reportedsuperconductivity-re lated effects -- though not true superconductivity -- at the torrid heights of 240 K, or -27 degrees F, which is warmer than many wintry nights in North Dakota.

Those results suggest an intriguing possibility. Says Bell Labs' Penzias: "Transition temperatures have increased by a factor of four in the past year. If temperatures are raised by another factor of four in the same period of time, we'll have room-temperature superconductors in less than a year." Adds IBM's Praveen Chaudhari: "All the mental barriers are gone. No one is asking how high it will go anymore." If room-temperature superconductivity is achieved, whether in a year or in a score of years, its impact will be incalculable. The need for refrigerators and insulation, even for liquid / nitrogen, will be gone. And the costs of this still futuristic technology could drop more dramatically than anyone expects. Says IBM's Paul Grant: "We're looking. Everyone is." Adds IBM's William Gallagher: "We shouldn't let our imaginations be constrained by things we now know about. We're just not able to imagine the things you can do."

CHART: TEXT NOT AVAILABLE

CREDIT: TIME chart by Joe Lertola

CAPTION: HEATING UP

DESCRIPTION: Highest known superconducting temperatures for various materials on a scale of absolute zero to over 100 Kelvin for the years 1911 to 1980, with illustration of scientist holding thermometer bounding up steps.

With reporting by Thomas McCarroll/New York, J. Madeleine Nash/Chicago and Dennis Wyss/San Francisco