We studied the voltage and temperature dependency of the dynamic conductance of normal metal–MgB2 junctions obtained either with the point-contact technique (with Au and Pt tips) or by making Ag-paint spots on the surface of MgB2 samples. The fit of the conductance curves with the generalized BTK model gives evidence of pure s-wave gap symmetry. The temperature dependency of the gap, measured in Ag-paint junctions (dirty limit), follows the standard BCS curve with 2Δ/kBTc=3.3. In out-of-plane, high-pressure point-contacts we obtained almost ideal Andreev reflection characteristics showing a single small s-wave gap Δ=2.6±0.2 meV (clean limit).
|Titolo:||Temperature and junction-type dependency of Andreev reflection in MgB2|
|Data di pubblicazione:||2002|
|Digital Object Identifier (DOI):||10.1016/S0022-3697(02)00229-9|
|Appare nelle tipologie:||1.1 Articolo in rivista|
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