Researchers at AT&T Bell Laboratories have produced a flexible superconducting wire that can carry at least 100 times more electrical current than any similar new ceramics, bringing practical uses of the materials significantly closer to reality.
The discovery, to be presented today at a scientific meeting in Boston, will help translate the new superconductors, which carry electricity without resistance, from scientific achievements into useful products.
"This is a major hurdle jumped," said Theodore H. Gabelle, professor of applied physics at Stanford University and a leading researcher in superconductivity. "It is the biggest step away from theory and toward making wires we can use in motors. It's very exciting."
A little more than a year ago, two IBM scientists touched off a worldwide race when they discovered a new class of ceramics that can carry electricity without resistance at temperatures far higher than had been considered possible.
Last month, the two -- J. Georg Bednorz and K. Alex Mueller -- were awarded the 1987 Nobel Prize in physics.
Since their work began, advances in superconductivity have been rapid, but no one had determined how to turn the brittle materials into the type of wires needed for motors and machines.
This advance is a major step in that direction. Led by senior researcher Sungho Jin, the Bell team created a superconducting wire from ceramics that can carry large amounts of current through magnetic fields.
Jin said he created the material by melting a superconducting ceramic made from a mixture of yttrium-barium and copper oxide and letting it solidify. This changed the chemical composition of the crystals involved, allowing them to pass electrical current much more efficiently.
In the past, when scientists at Bell labs and elsewhere had packed the ceramic crystals into wires, it dramatically reduced the wires' ability to carry power.
"Large-scale applications need wires," said Thomas D. Schlaback, department head in Bell's materials physics research lab. "Until now, we were able only to prove theoretically that the wires could be made. We now believe we have a good prospect of going the rest of the way."
Schlaback said many refinements are necessary before wires are available for common use. He added that the results are far short of those needed to achieve dramatic breakthroughs that many scientists are seeking.
Producing useful wires, along with ceramics that work at higher temperatures, is considered among the most important practical advances in superconductor research.
Practical superconductors promise to revolutionize most uses of electricity by eliminating waste of power inherent in ordinary conductors and by making possible new applications. Among the most widely discussed are high-speed trains riding a cushion of electromagnetism, more powerful supercomputers and a variety of medical devices.
At first, the amount of electricity carried by the new superconductors -- even when refrigerated by liquid nitrogen -- was about 100 amperes. The filament of a standard light bulb can carry at least 1,000 amps per square centimeter.
The Bell wire carries current at 7,400 amperes per square centimeter and, when passing through a magnetic field, carries enough current to light a standard bulb.
While that power level is slight, compared with the massive requirements of sophisticated electrical devices, it is far higher than past attempts.
"The really important achievement is that we believe this will take us even farther," Schlaback said. "This is a fundamental achievement, and we can all use it to get where we have to go."