The physics of the π phase shift in ferromagnetic Josephson junctions may enable a range of applications for spin-electronic devices and quantum computing. We investigate transitions from ``0'' to ``π'' states in Nb/Fe/Nb Josephson junctions by varying the Fe barrier thickness from 0.5 nm to 5.5 nm. From magnetic measurements we estimate for Fe a magnetic dead layer of about 1.1 nm. By fitting the characteristic voltage oscillations with existing theoretical models we extrapolate an exchange energy of 256 meV, a Fermi velocity of 1.98×105 m/s and an electron mean free path of 6.2 nm, in agreement with other reported values. From the temperature dependence of the ICRN product we show that its decay rate exhibits a nonmonotonic oscillatory behavior with the Fe barrier thickness.
@article{arxiv.cond-mat/0612235,
title = {0-pi oscillations in nanostructured Nb/Fe/Nb Josephson junctions},
author = {Samanta Piano and J. W. A. Robinson and G. Burnell and M. G. Blamire},
journal= {arXiv preprint arXiv:cond-mat/0612235},
year = {2008}
}
Comments
7 pages, 5 figures, accepted for publication in Eur. Phys. J. B