The effect of 3d paramagnetic impurities on superconductivity in quench-condensed amorphous Pb films
Abstract
A modified dilution refrigerator equipped with Sb, Pb and NiCr sources is used to carry out an in situ study of the effect of magnetic impurities (MI) on the <u>same quench-condensed Pb films. Si substrate with pre-deposited Au contacts is mounted in dilution unit and cool down to 5K. To ensure the electrical and possibly structural homogeneity down to monolayer thickness, we deposit a thin layer of Sb prior to the Pb evaporation. At a thickness above 8 ? the film exhibits superconductivity with well-defined resistive transition and Tc controlled by the film thickness. When a film of desired Tc is obtained we incrementally evaporate </u>MI onto the film by heating a NiCr wire at constant current and perform in situ measurements. We observe that Tc is continuously suppressed with increasing MI density while the resistive transitions remain sharp, although the MI induces significant filling of states inside the gap. The Tc as a function of MI density is well described by the Abrikosov-Gorkov theory regardless of the starting Tc and the pair-breaking strength of the MI appears to be independent of the degree of disorder.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2006
- Bibcode:
- 2006APS..MARH38007K