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    Analysis of the phonon spectrum emitted by superconducting Al-tunneling junctions at high quasiparticle injection rates
    (1981) Welte, Michael; Eisenmenger, Wolfgang
    The phonon spectrum emitted by superconducting Al-tunneling junctions is analyzed by experiments, in which two junctions of different energy gaps are used as phonon generator and detector. The energy gap of the Al-films is varied by the evaporation conditions. The experiments show clearly that the phonon spectrum and the quasiparticle distributions in the generator are strongly nonthermal and depend markedly on the primary tunneling injection. At high injection rates also significant consequences of gap reductions and instabilities are observed.
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    Enhancement of the Kapitza conductance at 0.32 meV phonon energy
    (1983) Heim, Ulrich; Schweizer, Rainer J.; Koblinger, Otto; Welte, Michael; Eisenmenger, Wolfgang
    Using quasimonochromatic relaxation phonons emitted by superconducting tunneling functions, the phonon transfer through real solid-liquid helium interfaces was tested. We found an enhancement of the energy transmission if the incident phonons exceed the threshold energy Eo = 0.32 meV. This sharp threshold energy shifts to 0.42 meV if the lighter isotope 3 He is used.
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    Observation of phonon frequency thresholds in the anomalous Kapitza resistance
    (1983) Koblinger, Otto; Heim, Ulrich; Welte, Michael; Eisenmenger, Wolfgang
    Phonons emitted by superconducting tunneling junctions into insulator crystal substrates exhibit a sharp amplitude reduction above 85 GHz if the tunneling diodes are covered by 4He. This is attributed to the onset of an enhanced phonon transport into helium.
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    Quasiparticle recombination time of superconducting tin films in a parallel magnetic field
    (1985) Holdik, Karl; Welte, Michael; Eisenmenger, Wolfgang
    The influence of a parallel magnetic field on the quasiparticle recombination time of superconducting tin tunneling junctions has been determined experimentally. The results are compared with the predictions of a theoretical model that takes into account the modification of the quasiparticle density of states by the applied magnetic field.