ISSN:
1573-7357
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract We investigated metallic point contacts between a tungsten tip and the superconducting heavy-fermion compounds. On lowering the temperature to belowT c the contact resistance drops by δR. Usually this change in resistance is interpreted by the Andreev-reflection process at the normal-superconducting interface. However, we found that δR does not scale with the inverse area of the orifice-as expected for Andreev reflection-but with the inverse radius and the specific resistivity in the normal state. Such a behaviour is characteristic for Maxwell's resistance being suppressed in the superconducting heavy-fermion phase. Additionally, the residual contact resistance at zerobias is strongly enhanced compared to the ballistic Sharvin contribution. We discuss the possible microscopic origin for the reduced or even absent Andreev-hole current and the enhanced residual resistance.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00754627
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