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0-pi oscillations in nanostructured Nb/Fe/Nb Josephson junctions

Samanta Piano·J. W. A. Robinson·G. Burnell·M. G. Blamire
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Abstract

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 $1.98 \times 10^5$ m/s and an electron mean free path of 6.2 nm, in agreement with other reported values. From the temperature dependence of the $I_CR_N$ product we show that its decay rate exhibits a nonmonotonic oscillatory behavior with the Fe barrier thickness.

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Samanta Piano, J. W. A. Robinson, G. Burnell, M. G. Blamire. 2007-07-10. 0-pi oscillations in nanostructured Nb/Fe/Nb Josephson junctions. https://doi.org/10.1140/epjb%2Fe2007-00210-8

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