We have studied temperature and field dependencies of the critical current IC in the Nb-Fe0.1Si0.9-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 IC(T) similar to the IC(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.
@article{arxiv.cond-mat/0606513,
title = {The 0 and the pi phase Josephson coupling through an insulating barrier with magnetic impurities},
author = {O. Vavra and S. Gazi and D. S. Golubovic and I. Vavra and J. Derer and J. Verbeeck and G. Van Tendeloo and V. V. Moshchalkov},
journal= {arXiv preprint arXiv:cond-mat/0606513},
year = {2009}
}