Inhaltszusammenfassung

We report the first low-temperature-irradiation experiment of thin films of the Chevrel-phase superconductor PbMo6S8 with fast ions (20-MeV sulfur). The films were prepared by dc magnetron sputtering and had superconducting critical temperatures Tc up to 12.85 K (midpoint) with onsets of superconductivity up to 14.7 K. As a function of fluence, Tc, the initial slope of the upper critical field (dHc2/dT)T=Tc, the low-temperature resistivity ?(16 K), and its temperature dependence ?(T) have bee...We report the first low-temperature-irradiation experiment of thin films of the Chevrel-phase superconductor PbMo6S8 with fast ions (20-MeV sulfur). The films were prepared by dc magnetron sputtering and had superconducting critical temperatures Tc up to 12.85 K (midpoint) with onsets of superconductivity up to 14.7 K. As a function of fluence, Tc, the initial slope of the upper critical field (dHc2/dT)T=Tc, the low-temperature resistivity ?(16 K), and its temperature dependence ?(T) have been measured. The Hc2(T) and ? data indicate a defect-induced reduction of the electronic density of states at the Fermi level N(EF). This appears to be responsible for the strong decrease of Tc which drops below 1.2 K at the comparatively very low fluence of 1014 cm-2. The Tc decrease is accompanied by a change in the behavior of ?(T) from metallic with a residual resistance ratio of about two to less than one at a fluence of only 3.9×1013 cm-2 where Tc is still 6.32 K. The resistance ratio decreases further with irradiation and is less than 0.5 at 6.5×1014 cm-2. We estimate the obtained defect concentrations and propose a simple model which could explain the observed experimental results. » weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
Physik der kondensierten Materie

DDC Sachgruppe:
Physik