Odd spin-triplet superconductivity in a multilayered superconductor-ferromagnet Josephson junction

Abstract

We study the dc Josephson effect in a diffusive multilayered SF′FF′S structure, where S is a superconductor and F and F′ are different ferromagnets. We assume that the exchange energies in the F′ and F layers are different (h and H, respectively) and the middle F layer consists of two layers with parallel or antiparallel magnetization vectors M. The M vectors in the left and right F′ layers are generally not collinear to those in the F layer. In the limit of a weak proximity effect we use a linearized Usadel equation. Solving this equation, we calculate the Josephson critical current for arbitrary temperatures, arbitrary thicknesses of the F′ and F layers (Lh and LH) in the case of parallel and antiparallel M orientations in the F layer. The part of the critical current IcSR formed by the short-range singlet and S=0 triplet condensate components decays on a short length ξH=D/H, whereas the part IcLR due to the long-range triplet |S|=1 component decreases with increasing LH on the length ξN=D/πT. Our results are in a qualitative agreement with the experiment [T. S. Khaire, M. A. Khasawneh, W. P. Pratt, Jr., and N. O. Birge, Phys. Rev. Lett. 104, 137002 (2010)].

Source-reported materials — not catalogue approval

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