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Observation of multiple Andreev reflections in superconducting tunnel junctions

A. W. Kleinsasser, R. E. Miller, W. H. Mallison, G. B. Arnold

DOI 10.1103/PhysRevLett.72.1738 · Physical Review Letters

T1

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Abstract

We describe measurements on high-current-density Nb-AlOx-Nb tunnel junctions and demonstrate that the development of excess subgap current with increasing barrier transparency is the result of multiple Andreev reflections. We present a model for the barrier consistent with measured junction resistance, the high transparency required for multiple traversals, and the observed single-particle and Josephson characteristics. We argue that excess subgap current and subharmonic gap structure in superconducting tunnel junctions are generally likely to be due to pinhole defects in the barriers.

Source-reported materials — not catalogue approval

FormulaReported Tc (K)Pressure (GPa)Type
Nb

Archive — visibility unverified

Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.

4.2Pressure not reportedunknown

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