Magnetics Business & Technology - Spring 2013 - (Page 4)

EDITOR’S CHOICE Iron-Based Superconductors Set New Performance Records The road to a sustainably powered future may be paved with superconductors. When chilled to frigid temperatures hundreds of degrees Celsius below zero, these remarkable materials are singularly capable of perfectly conducting electric current. To meet growing global energy demands, the entire energy infrastructure would benefit tremendously from incorporating new electricity generation, storage and delivery technologies that use superconducting wires. But strict limits on temperature, high manufacturing costs and the dampening effects of high-magnetic fields currently impede widespread adoption. Now, a collaboration led by scientists at the US DOE’s Brookhaven National Laboratory have created a high performance iron-based superconducting wire that opens new pathways for some of the most essential and energy-intensive technologies in the world. These custom-grown materials carry tremendous current under exceptionally high magnetic fields, an order of magnitude higher than those found in wind turbines, magnetic resonance imaging (MRI) machines and even particle accelerators. The results demonstrate a unique layered structure that outperforms competing low-temperature superconducting wires, while avoiding the manufacturing costs associated with high-temper- Brookhaven physicists Weidong Si (left) and Qiang Li look into the vacuum chamature superconductor (HTS) alternatives. ber where the new high-field iron-based “With the focused effort of this collaboration, superconductors are made through a prowe made a major breakthrough in iron chalcogen- cess called pulsed-laser deposition. ide-based superconducting films that not only sets the record for maximum critical current under high magnetic fields, but also raises the operating temperature for the material,” said Brookhaven Lab physicist Weidong Si. “That could mean conducting more electricity in a wide range of technologies while potentially using less energy to cool down the superconducting wire.” Copper-oxide (cuprate) high-temperature superconductors are a leading candidate for advanced energy applications, but these ceramic-based materials are very brittle and require a complicated and expensive multilayer synthesis process. Beyond that, anisotropies, structural asymmetries that prevent current from flowing evenly in different directions across a material, limit overall efficiency in these compounds. Iron-based superconductors, however, are mechanically semi-metallic and therefore considerably less fragile. They can also be more easily shaped into the kinds of long wires needed in devices like massive offshore wind turbines, and they exhibit nearly isotropic behavior in magnetic fields, which allows for easier technology integration. The scientists synthesized this novel film of iron, selenium and tellurium to push existing performance parameters. In addition to the raw materials being relatively inexpensive, the synthesis process itself can be performed at just half the temperature of cuprate-based HTS alternatives, or approximately 400°C. The team used a thin film fabrication technique called pulsed-laser deposition, which uses a high-power laser to vaporize materials that are then collected in layers on a substrate. This complex technique is a bit like carefully collecting the gas as it rises above a boiling pot, only with nearly atomic-level precision. “A key breakthrough here is the discovery that adding layers of cerium-oxide in between the films and substrates dramatically increased the superconductor’s critical current density, or maximum electricity load, as well as the critical temperature at which the material becomes superconducting,” said Brookhaven Lab physicist Qiang Li, head of the Advanced Energy Materials Group and leader of this study. “That critical temperature threshold rose 30 percent over the same compound made without this layering process, still a very cold 4 Magnetics Business & Technology • Spring 2013 Volume 12, Issue 1 Editor & Publisher David Webster Director of Content Nick Depperschmidt Senior Editor Shannon Given Associate Editor Heather Krier Contributing Editor Stan Trout News Editors Sue Hannebrink, Jeremy Fleming Scott Webster, Robert Schaudt Director of Support Services/Circulation Marc Vang Databases/Directories Ross Webster Advertising Sales and Marketing Jeremy Fleming, Director of Sales Scott Webster, Advertising Sales Manager Production Julie Hammond Webmaster Brie Ryden Administration Marsha Grillo, Director Julie Williams, Office Manager Magnetics Business & Technology (ISSN #1535-1998) is a publication of Webcom Communications Corp. 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Table of Contents for the Digital Edition of Magnetics Business & Technology - Spring 2013

Magnetics Business & Technology - Spring 2013
Editor's Choice
Dysprosium-Free Rare Earth Magnets for High Temperature Applications
Research & Development
Simulating the Toyota Prius Electric Motor
Magnets • Materials • Measurement
Application • Component Developments
Industry News
Marketplace/Advertising Index
Spontaneous Thoughts: Dysprosium 2.0

Magnetics Business & Technology - Spring 2013