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Subject: search.filters.subject.530Institute: search.filters.UBSInstitut.Sonstige EinrichtungStart date: 1980End date: 1989Author: search.filters.author.Keller, Heimo J.Author: search.filters.author.Grimm, Hans

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Now showing 1 - 4 of 4
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    ODMR of triplet states of organic electron donors
    (1986) Grimm, Hans; Schweitzer, Dieter; Hausser, Karl H.; Keller, Heimo J.
    Energies of the first excited triplet states and triplet zero field splitting parameters /D/ and /E/ of several organic donors - usually used for the preparation of organic metals and superconductors - are reported.
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    Superconductivity in polycrystalline pressed samples of organic metals
    (1989) Schweitzer, Dieter; Gärtner, Stephan; Grimm, Hans; Gogu, Emil; Keller, Heimo J.
    We report bulk superconductivity at ambient pressure in polycrystalline pressed samples of αt-(BEDT-TTF)2I3. As in single crystals of αt-(BEDT-TTF)2I3 the onset for superconductivity in the polycrystalline pressed samples lies at about 9K but the transition is broader. Zero resistivity is observed at 2.2K and the middle of the transition is found at 5K. The measurement of the ac susceptibility shows that at 2K about 50% of the sample is superconducting, but at this temperature the transition is still not saturated. The observation of bulk superconductivity in this polycrystalline pressed samples is of special interest because it demonstrates that organic superconductors can be used in principle as well for the production of electronic devices such as squids and superconducting cables. In addition the finding of bulk superconductivity in large pressed samples of crystallites of the typical diameter of 1μm of an organic metal indicates that the observation of superconductivity in organic polymers should be possible as well.
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    Raman studies of the organic superconductor β-(BEDT-TTF)2IAuI
    (1987) Swietlik, Roman; Grimm, Hans; Schweitzer, Dieter; Keller, Heimo J.
    The resonance Raman spectra of (IAuI)-anions in the organic superconductor. The resonance Raman spectra of (IAuI)-anions in the organic superconductor β-(BEDT-TTF)IAuI as well as in the electrolyte salt n-Bu4AuI2 are investigated. In contrast to β-(BEDT-TTF)2I3 in the crystals of β-(BEDT-TTF)2IAuI at low temperature only one Raman line at 120cm-1 corresponding to the symmetrical stretching mode of the (IAuI)-anion is observed. No distinct change in the Raman spectra is observed at the superconducting transition.
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    Superconductivity at 7.5 K and ambient pressure in polycrystalline pressed samples of βp-(BEDT-TTF)2I3
    (1989) Schweitzer, Dieter; Gogu, Emil; Grimm, Hans; Kahlich, Siegfried; Keller, Heimo J.
    Recently, bulk superconductivity at ambient pressure in polycrystalline pressed samples of an organic metal - α-(BEDT-TTF)2I3 - was observed. This is a remarkable fact because this finding shows that organic superconductors can in principle be used for the production of electronic devices, such as squids, and might even be suitable for the preparation of superconducting cables similar to the high temperature superconductors of the copper oxides.