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•Long-range order in metallic glass

cerium-aluminum glassThe research team, including Carnegie’s Ho-Kwang (Dave) Mao, observed that crystalline long-range topological order can form in metallic glass made from cerium and aluminum. Their research reveals the possibility of creating a metallic glass that is organized on a larger scale. The team determined that the atomic structures of cerium and aluminum prevent the glass from assuming the highly ordered state at normal pressures. But under intense pressure at 25 gigapascals, an electron in cerium shifts, allowing a face-centered cubic single crystal structure to be created. When the glass was brought back to ambient pressure, the new structural order was preserved.

Metallic glasses are a hot research topic, because they are less brittle than ordinary glasses and more resilient than conventional metals. “These exciting results demonstrate that pressurized cerium-aluminum glass could be a favorable system for discovering the long-sought-after perfect glass,” Mao said. “This situation could also exist in other metallic glasses.”

Please see the article on Science 322:6036. 1404-1406, 17 June 2011 issue, and Carnegie News.

Image: An illustration of the process through which the atoms in cerium-aluminum glass become ordered and develop a crystalline structure under high pressure within a diamond-anvil cell.