Title: Magnetic field dependence of the Andreev reflection structure in the conductivity of S-N point contacts
Abstract: Current—voltage (I—V) characteristics of point contacts between the superconductors Sn, In, or Nb and a normal metal were measured in a magnetic field. The dV/dI curves of the point contacts show features caused by Andreev reflection at the S-N interface which persist well above Bcbulk of the bulk sample. Shortening of the elastic mean free path in the contact area of the superconductor caused by structural defects results in type-II superconductivity in the point contact and an enhancement of BcPC. A satisfactory description of the dV/dI curves within the BTK theory was only possible by taking into account a lifetime broadening Γ of the density of states in the superconductor. Γ is found to be independent of temperature and increases in a magnetic field. Furthermore, Γ is sufficiently higher for Nb than for Sn. The temperature and magnetic field dependencies of the pair potential Δ are also evaluated and discussed.
Publication Year: 1996
Publication Date: 1996-02-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 32
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