Research Fellows Directory
Professor Kosmas Prassides
University of Durham
Metals are used for electricity transmission, but valuable energy is lost as heat because of electrical resistance. Superconductors have no electrical resistance and can carry electricity without losing it, so finding superconductors which work at as high a temperature as possible is important. My recent work shows for the first time how controlling the arrangement of molecules in a high temperature superconductor controls its properties. This is possible because we have found two arrangements of the same basic molecular unit which have both superconducting and magnetic properties. In the well-researched high temperature superconducting copper oxides only one spatial arrangement of the electronically active Cu2+ units, the two-dimensional square lattice, is available to study the competition between the co-operative electronic states of magnetic order and superconductivity. On the other hand, the spherical molecular C603- anion can be packed in fundamentally distinct three-dimensional arrangements. My recent work has shown that both fcc and bcc packings of C603- at the same Cs3C60 composition are accessible. Since both packings sustain superconductivity and magnetism, we are able for the first time to show how the spatial arrangement of the electronically active units controls these two ground states of key importance for the understanding of high-temperature superconductivity.
Interests and expertise (Subject groups)