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October 09, 2009

Five Year Project To Make Nanostructured Boron Doped Superconducting Wires


Wires made up of yarns spun from millions of carbon nanotube bundles may help make superconductivity practical.

Researchers from UT Dallas, Clemson University and Yale University are using science on the nanoscale to address one of the most elusive challenges in physics—the discovery of room temperature superconductivity. With that as the ultimate goal, the team is working to develop superconducting wires made from nanotubes that carry high currents at the temperature of liquid nitrogen, or higher.

With a $3 million research grant from the Air Force Office of Scientific Research (AFOSR), the team has embarked on a five-year project to invent new superconducting wires based on highly engineered nanomaterials, each component thousands of times smaller than a human hair. Such wires would be used for applications ranging from magnets for Magnetic Resonance Imaging to replacing energy-wasting copper in power transmission lines.

Modern high temperature superconducting materials are too brittle, expensive and deficient in electronic properties for wide-scale application. We hope to overcome those limitations by fabricating wires from nanotubes, using carbon nanotubes or other nanotubes enhanced by atoms like boron, nitrogen or sulfur.”

According to Zakhidov, who is a professor of physics, as much as 30 percent of electrical energy can be lost as heat when electricity travels through power lines. Superconducting materials promise enormous environmental and energy savings.

“Making superconducting wires and cables from nanofibers and nanoparticles presents special challenges that go beyond the discovery of new superconductors,” Baughman said. “For example, for each pound of superconducting wire, it may be necessary to assemble more than 3 billion miles of individual nanotubes—and the goal is to achieve this assembly at commercially useful rates. For this task, we are inventing radically new methods for making superconducting wires.”

Dr. Lisa Pfefferle, professor of chemical engineering at Yale University and member of the research team, is experimenting with new types of nanofibers that have been synthesized by her team using elements like boron.

Team member Dr. Apparao Rao, professor of physics at Clemson University, has already produced superconducting nanotubes by a process called pulsed laser ablation. The process results in carbon nanotubes “doped” with boron that superconduct at higher temperatures than other carbon based materials—but still at relatively low temperatures.



Dr. Myron Salamon, dean of the School of Natural Sciences and Mathematics, will evaluate the team’s new superconductors to test the maximum temperature of superconductivity as a function of current and power transmitted, which is a crucial factor for using these materials in power systems.

“There’s always been a sense that we can enhance superconductivity by using lighter materials,” Salamon said. “Wires made from ultra-light nanotubes can allow atoms to vibrate easily, which helps with superconductivity. There’s good evidence that carbon-based materials, like dopant modified carbon nanotubes, might make good superconductors.”


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