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[Tvoivozhd <tvoivozd AT infionline.net>]

Still need to operate at liquid nitrogen temperatures, so not useful in 
small-scale devices---still, the Super Superconductor offers large 
economy in operation in a large device.


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/Source:/       *Los Alamos National Laboratory*        
/Date:/         2004-09-10
/URL:/  http://www.sciencedaily.com/releases/2004/09/040910080120.htm

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   Nanotechnology Leads To Discovery Of Super Superconductors

LOS ALAMOS, N.M., Sept. 9, 2004 -- University of California scientists 
working at Los Alamos National Laboratory with a researcher from the 
University of Cambridge have demonstrated a simple and industrially 
scaleable method for improving the current densities of superconducting 
coated conductors in magnetic field environments. The discovery has the 
potential to increase the already impressive carrying capacity of 
superconducting wires and tapes by as much as 200 to 500 percent in 
certain uses, like motors and generators, where high magnetic fields 
diminish current densities.

In research reported in the journal Nature Materials, University of 
Cambridge scientist Judith Macmanus-Driscoll and her Los Alamos 
colleagues discovered that when the compound barium zirconate is 
deposited simultaneously with the yttrium-barium-copper-oxide 
superconductor it naturally forms nanoscale particles embedded in 
superconductor films. The result was a two to five fold increase in the 
current densities of coated conductors in high magnetic fields operating 
at liquid nitrogen temperatures.

Superconducting wires and tapes carry hundreds of times more electrical 
current than conventional copper wires with little or no electrical 
resistance. Superconducting technology is poised to bring substantial 
energy efficiencies to electrical power transmission systems in the 
United States. Much of the excitement caused by this discovery is due to 
the fact that the process can be easily and economically incorporated 
into commercial processing of the superconductors. The advance is 
important for the development of powerful, energy efficient 
superconducting electric motors and generators for civilian and military 
applications. The Laboratory conducts research and development of 
high-temperature superconducting tapes under the auspices of Los Alamos 
Superconductivity Technology Center (STC).

Dean Peterson, leader of the STC, said, "This is a significant technical 
advancement because it means we are now beginning to understand how to 
control defects in these superconducting materials and use them to our 
advantage. This was the first time we have been able to control the 
structural defects and in doing so, better engineer the material's 
structure to optimize performance."

Contrary to what one might think, the presence of certain types of 
defects in the superconducting film is not a problem, but a necessity. 
Early high temperature superconductivity research had the goal of 
eliminating large-scale defects, which effectively blocked the flow of 
electrical currents through the material. This required an ordering of 
superconducting grains, much like the bricks in a smooth road, allowing 
the unimpeded flow of high-density electrical currents. Scientists later 
discovered that small, nanoscale defects are required to maintain high 
current densities in superconductors, particularly in the presence of 
high magnetic fields. Nanoscale refers to defect sizes roughly 50-100 
atoms across.

Because magnetic fields create small swirls of current in a 
superconductor called vortices, much like tornadoes in the air, that 
move through the material under the influence of electrical currents 
causing resistance to the flow of the current, the nanoscale defects 
immobilize or "pin" the vortices allowing the current to flow without 
resistance. These nanoscale defects can come in various forms ranging 
from small particles to flat plates and long string-like objects. 
Previous attempts to produce dense arrays of these types of small-scale 
defects, such as irradiation by fast heavy ions, were impractical for 
commercial production or difficult to control in a reproducible manner.

In addition to Macmanus-Driscoll and Peterson, other members of the team 
included Stephen Foltyn, Quanxi Jia, Haiyan Wang, Adriana Serquis, 
Leonardo Civale, Boris Maiorov, Marilyn Hawley and Martin Maley, all of 
Los Alamos. The research was conducted under the auspices of the Los 
Alamos Superconductivity Technology Center and was funded by the DOE's 
Office of Electric Transmission and Distribution.

###

Los Alamos National Laboratory is operated by the University of 
California for the National Nuclear Security Administration (NNSA) of 
the U.S. Department of Energy and works in partnership with NNSA's 
Sandia and Lawrence Livermore national laboratories to support NNSA in 
its mission.

Los Alamos enhances global security by ensuring the safety and 
reliability of the U.S. nuclear deterrent, developing technologies to 
reduce threats from weapons of mass destruction, and solving problems 
related to defense, energy, environment, infrastructure, health and 
national security concerns.

*Editor's Note:* The original news release can be found here 
<http://www.lanl.gov/worldview/news/releases/archive/04-075.shtml>.

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/This story has been adapted from a news release issued by Los Alamos 
National Laboratory./