Of the 92 naturally occurring elements, add another to the list of those that are superconductors.
James S. Schilling, Ph.D., professor of physics in Arts & Sciences at Washington University in St. Louis, and Mathew Debessai, Ph.D., his doctoral student at the time discovered that europium becomes superconducting at 1.8 K (-456 F) and 80 GPa (790,000 atmospheres) of pressure, making it the 53rd known elemental superconductor and the 23rd at high pressure.
Debessai, who received his doctorate in physics at Washington University's Commencement May 15, 2009, is now a postdoctoral research associate at Washington State University.
"It has been seven years since someone discovered a new elemental superconductor," Schilling said. "It gets harder and harder because there are fewer elements left in the periodic table."
This discovery adds data to help improve scientists' theoretical understanding of superconductivity, which could lead to the design of room-temperature superconductors that could be used for efficient energy transport and storage.
The results are published in the May 15, 2009, issue of Physical Review Letters in an article titled "Pressure-induced Superconducting State of Europium Metal at Low Temperatures."
Schilling's research is supported by a four-year $500,000 grant from the National Science Foundation, Division of Materials Research.
Europium belongs to a group of elements called the rare earth elements. These elements are magnetic; therefore, they are not superconductors.
"Superconductivity and magnetism hate each other. To get superconductivity, you have to kill the magnetism," Schilling explained.
Of the rare earths, europium is most likely to lose its magnetism under high pressures due to its electronic structure. In an elemental solid almost all rare earths are trivalent, which means that each atom releases three electrons to conduct electricity.'/>"/>
|Contact: James S. Schilling|
Washington University in St. Louis