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| Book/Report | FZJ-2018-02381 |
1984
Kernforschungsanlage Jülich, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/18022
Report No.: Juel-1921
Abstract: There exists a class of ternary molybdenum chalcogenides EuMo$_{6}$S$_{8}$, SrMo$_{6}$S$_{8}$ and BaMo$_{6}$S$_{8}$ with divalent metal cations, which are not superconducting. This is due to the fact that narrow degenerate conduction bands lead to a Jahn-Teller like lattice distortion at 105K, 134K and 175K. Detailed investigations of this structural phase transitions require single crystal samples, which are grown using a gas phase transport reaction. By means of susceptibility measurements, a low density of states at the fermienergy is observed in the low temperature triclinic structure. The lack of superconductivity can be explained by this low density of states. Pressure induces superconductivity in these compounds ; the critical pressure is 7kbar for EuMo$_{6}$S$_{8}$, IlKbar for SrMo$_{6}$S$_{8}$ and 19Kbar for BaMo$_{6}$S$_{8}$. The bulk nature of the superconductivity is demonstrated for SrMo$_{6}$S$_{8}$ by Meissner-Effect measurements under pressure.
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