Washington, Nov 14 : National Institute of Standards and Technology (NIST) researchers have decoded the mysterious mechanisms behind the high-temperature superconductors that industry hopes will find wide use in next-generation systems for storing, distributing and using electricity.
The advance could pave the way for next-generation systems for storing, distributing and using electricity.
Many materials become superconductors at temperatures approaching absolute zero, capable of carrying vast amounts of electrical current with no resistance. In such low-temperature superconductors, magnetism can actually shatter the fragile superconductive state.
In 1986, scientists discovered "high temperature" (HTc) superconductors capable of operating much warmer than the previous limit of 30 degrees above absolute zero.
In fact, today's copper-oxide materials are superconductive in liquid nitrogen, a bargain-priced coolant that goes up to a balmy 77 degrees above absolute zero.
In early 2008 Japanese researchers announced discovery of a new class of iron-based HTc superconductors.
Such materials are not only easy to shape into wires and otherwise commercialize than today's copper-oxides, but they also provide for fresh new subjects which can lead to development and testing of theories about HTc superconductivity's origins. For the study, the scientist used beams of neutrons to peek into a superconductor's atomic structure.
They first found iron-based superconductors to be similar to copper-oxide materials in how "doping" (adding specific elements to insulators in or around a HTc superconductor) influences their magnetic properties and superconductivity.
Then they tested the iron-based material** without doping it.
It was found that under moderate pressure, the volume of the material's crystal structure compressed an unusually high 5 percent. Intriguingly, it also became superconductive without a hint of magnetism.
NIST Fellow Jeffrey Lynn said that the iron-based material's behaviour under pressure may suggest the remarkable possibility of an entirely different mechanism behind superconductivity than with copper oxide materials.
Understanding the origin of the superconductivity will help engineers tailor materials to specific applications, guide materials scientists in the search for new materials with improved properties and, scientists hope, usher in higher-temperature superconductors.