Sandia National Laboratories researchers have made a new superconducting film of material they say could have important ramifications for future generations of microelectronics and computers.
"These films are really like hitting the jackpot, and I think we did," David S. Ginley, supervisor of Sandia's semiconductor materials division, said this week.The thin thallium-barium-copper oxide superconducting material loses all resistance to electricity at minus 285 degrees Fahrenheit, which Ginley said is 13 degrees warmer than previously achieved in thin film superconductors.
Superconductivity is the ability of some materials to conduct electricity without loss because of resistance. Improved superconductors could lead the way to powerful and compact computers, high-speed floating trains and other advances, scientists say.
The thallium-barium-copper compound itself was developed by Allen Hermann, chairman of the physics department at the University of Arkansas, and Zhengzhi Sheng, a chemistry professor at the university.
The Sandia researchers, including James F. Kwak, Ronald P. Hellmer, Richard J. Baughman, Eugene L. Venturini and Bruno Morosin, have been working on the new thallium-based material for nine weeks, Ginley said.
The films made by the researchers are about seven-tenths of a micrometer thick and are deposited by layers on a substrate, which is the material the film is put on.
"We heat the metals with a controlled beam of electrons, which vaporizes the metals onto the substrate," Ginley said.
The materials are then heated and cooled twice "and that's what makes them superconducting," Ginley said.
The key to making the materials successfully is to carefully control the thallium content of the film during the heating and cooling process, called anealing, the researchers said.
Hermann, who spoke with The Associated Press in a telephone interview from Fayetteville, Ark., said he and Sheng announced their discovery of the thallium-based compound Feb. 15.
"I think they did a terrific job," Hermann said of the Sandia researchers. "I'm very excited about their work.
"They can be used on one-dimensional substrates, like wire or fiber. This is very exciting to think about now in the commercial realm of generators or motors or magnets," Hermann said.
Traditional metal superconductors must be cooled to around minus 460 degrees Fahrenheit using expensive liquid helium. But the new superconductors can be cooled with cheap liquid nitrogen.