Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 22: Transport: Poster Session
TT 22.33: Poster
Mittwoch, 27. Februar 2008, 14:00–18:00, Poster B
Conductance measurements on palladium breakjunctions with superconducting leads — •Stefan Egle, Cécile Bacca, Christian Schirm, and Elke Scheer — Department of Physics, University of Konstanz
We will present our recent results of palladium nanobridges connected by superconducting leads of aluminium. The structures are fabricated by using electron beam lithography and two-step shadow evaporation. By means of the mechanically controllable break junction (MCBJ) technique we are able to open the bridges to a one-atom contact and close again repeatedly at low temperatures, thus obtaining conductance histograms. Studying the properties of these palladium atomic point contacts at 270mK, we show the influence of the superconducting leads onto the electronic properties of palladium (proximity effect) by measuring the differential resistance. As expected, we observe a decrease of the dV/dI for voltages |V| ≤ 120µV < ΔAl=180µ V which increases again when either the external magnetic field or the temperature is raised. Investigating the disappearence of this effect, we determine the critical values Bc and Tc.