Researchers Bridge Superconductivity Gap

University of California scientists at Los Alamos National Laboratory working with a researcher from Chonnam National University in South Korea have found that magnetic fluctuations appear to be responsible for superconductivity in plutonium-cobalt-pentagallium (PuCoGa5). The discovery of this “unconventional superconductivity” may lead scientists to a new class of superconducting materials and toward eventually synthesizing “room-temperature” superconductors.

As reported in Nature, Nicholas Curro and a team of researchers provide evidence of how magnetic fluctuations, rather than interactions mediated by tiny vibrations in the underlying crystal structure, may be responsible for the electron pairing that produces superconductivity in the mixture of plutonium, cobalt and gallium.

Since the discovery at Los Alamos of PuCoGa5 roughly two years ago, a burning question has been whether the compound was just another garden-variety s-wave superconductor or an unconventional one mediated by magnetic fluctuations, a d-wave superconductor.

Although the temperatures at which superconductivity is observed are usually quite low, a handful of compounds like PuCoGa5 have been found to possess super-conductivity at temperatures warmer than -427°F. Even though that temperature seems low, PuCoGa5 possesses the highest superconducting transition temperature among actinide-based compounds found so far. This “unconventional superconductivity” suggests that PuCoGa5 may be one of a very small handful of superconductors whose superconductivity actually derives from magnetic correlations.

The discovery is the result of collaboration between the Laboratory’s Materials Science and Technology and Theoretical divisions. Curro’s team includes Tod Caldwell, Eric Bauer, Luis Morales, Yunkyu Bang, Matthias Graf, Alexander Balatsky, Joe Thompson and John Sarrao.

For more details, visit lanl.gov.