SCIENTISTS may not after all have to rely on ceramic oxides for high-temperature superconductors in future. Until now, researchers believed that these were the only suitable materials, but Japanese chemists at the University of Tokyo have now made a compound that remains superconducting up to a critical temperature (Tc) of 11.4 kelvin at normal pressures. The compound is organic.
The critical temperature may not seem very impressive when compared to ceramic compounds, but it is the highest yet for an organic superconductor. The critical temperatures that researchers had previously obtained were between 2 and 8 K.
The new compound, whose chemical formula is represented as k-(BEDT-TTF)2Cu(NCS)2, belongs to a class of materials known as organic radical-cation salts. The molecules in the compound comprise an organic, positively charged radical-cation. This has an unpaired electron, combined with a negative anion. The cation consists of flat rings of alternating single and double bonds ...
To continue reading this article, subscribe to receive access to all of newscientist.com, including 20 years of archive content.