December 01 2008 / by Garry Golden
Category: Energy Year: Beyond Rating: 2
Scientists at Brookhaven National Laboratory (US DoE) have developed a material that could advance our understanding of superconductivity and lead to more efficiency electrical transmission lines.
The material appears to be a superconductor but only in two dimensions, and at a higher temperature than ordinary 3-D superconductivity. The material is based on an unusual pattern of charge and magnetism “stripes” that many researchers long assumed as incompatible with superconductivity.
'The basic idea behind superconductivity is that electrons, which ordinarily repel one another because they have like charges, pair up to carry electrical current with no resistance' along high powered transmission lines. Conventional metallic superconductors do this at temperatures near absolute zero (0 kelvin or -273 degrees Celsius), requiring expensive cooling systems.
“Our basic research goal is to understand why and how these materials act as superconductors,” said Brookhaven physicist John Tranquada, who led the research. “The ultimate practical goal would be to use that understanding to develop improved bulk superconductors — ones that operate at temperatures warm enough to make them useful for real-world applications such as high-efficiency power lines.”
What happened at Brookhaven National Laboratory?
Brookhaven physicist John Tranquada and his colleagues are working with a layered material made of lanthanum, barium, copper, and oxygen (LBCO) where the ratio of barium to copper atoms is exactly 1 to 8. LBCO can act as a “high-temperature” superconductor with a peak operating temperature of 32 K. But at the mysterious 1:8 ratio, the transition temperature at which superconductivity sets in drops way down toward absolute zero.
Stripe order in the copper oxide planes involves both a modulation of the charge density (blue), detectable with x-ray diffraction, and a modulation of the arrangement of magnetic dipole moments (spin directions) on copper atoms (magenta arrows), detectable with neutron diffraction.
The research, conducted in part at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory, will appear in the November 2008 issue of Physical Review B