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The 0 and the pi phase Josephson coupling through an insulating barrier with magnetic impurities

O. Vavra·S. Gazi·D. S. Golubovic·I. Vavra·J. Derer·J. Verbeeck·G. Van Tendeloo·V. V. Moshchalkov
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Abstract

We have studied temperature and field dependencies of the critical current $I_{C}$ in the Nb-Fe$_{0.1}$Si$_{0.9}$-Nb Josephson junction with tunneling barrier formed by paramagnetic insulator. We demonstrate that in these junctions the co-existence of both the 0 and the $π$ states within one tunnel junction takes place which leads to the appearance of a sharp cusp in the temperature dependence $I_{C}(T)$ similar to the $I_{C}(T)$ cusp found for the $0-π$ transition in metallic $π$ junctions. This cusp is not related to the $0-π$ temperature induced transition itself, but is caused by the different temperature dependencies of the opposing 0 and $π$ supercurrents through the barrier.

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O. Vavra, S. Gazi, D. S. Golubovic, I. Vavra, J. Derer, J. Verbeeck, G. Van Tendeloo, V. V. Moshchalkov. 2006-06-20. The 0 and the pi phase Josephson coupling through an insulating barrier with magnetic impurities. https://doi.org/10.1103/physrevb.74.020502

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