Developments to Watch
SUPERCONDUCTIVE CERAMICS ON A SHOESTRING
Talk about low budgets. Andrew T. Hunt, a PhD student at Georgia Institute of Technology, wanted to try a different approach for creating thin films of ceramic materials. When a professor wouldn't O. K. the experiment, Hunt set up a plywood table in his backyard, and, using $250 worth of equipment, deposited a one-micron-thick layer of superconducting material on a crystal of magnesium oxide. He used an artist's airbrush and a blend of powdered yttrium, barium, and copper compounds dissolved in an everyday solvent, xylene. He put extra oxygen into the compressed air, then ignited the spray. Some of the resulting gunk landed on the crystal. The crude film showed hints of superconductivity at around 85 degrees Kelvin, above the boiling temperature of liquid nitrogen.
The technique, says Brent Carter, a Georgia Tech assistant professor of materials science, is a promising alternative to the current technology, chemical-vapor deposition. Hunt's combustion chemical-vapor deposition doesn't require costly vacuum chambers or furnaces. It has already been used to create other thin films, including yttrium-stabilized zirconia for wear resistance and insulation. Georgia Tech Research Corp. and Hunt have applied for a patent on the process.EDITED BY WILLIAM D. MARBACH