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Proximity effects in the superconductor / heavy fermion bilayer system Nb / CeCu_6

A. Otop·R. W. A. Hendrikx·M. B. S. Hesselberth·C. Ciuhu·A. Lodder·J. Aarts
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Abstract

We have investigated the proximity effect between a superconductor (Nb) and a 'Heavy Fermion' system (CeCu_6) by measuring critical temperatures $T_c$ and parallel critical fields H_{c2}^{\parallel}(T) of Nb films with varying thickness deposited on 75 nm thick films of CeCu_6, and comparing the results with the behavior of similar films deposited on the normal metal Cu. For Nb on CeCu_6 we find a strong decrease of T_c with decreasing Nb thickness and a finite critical thickness of the order of 10 nm. Also, dimensional crossovers in H_{c2}^{\parallel}(T) are completely absent, in strong contrast with Nb/Cu. Analysis of the data by a proximity effect model based on the Takahashi-Tachiki theory shows that the data can be explained by taking into account both the high effective mass (or low electronic diffusion constant), {\it and} the large density of states at the Fermi energy which characterize the Heavy Fermion metal.

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A. Otop, R. W. A. Hendrikx, M. B. S. Hesselberth, C. Ciuhu, A. Lodder, J. Aarts. 2003-03-19. Proximity effects in the superconductor / heavy fermion bilayer system Nb / CeCu_6. https://doi.org/10.1209/epl%2Fi2003-00138-7

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