Nonsinusoidal current-phase relations and the $0-\pi$ transition in diffusive ferromagnetic Josephson junctions

Abstract

We study the effect of the interfacial transparency on the Josephson current in a diffusive ferromagnetic contact between two superconductors. In contrast to the cases of the fully transparent and the low-transparency interfaces, the current-phase relation is shown to be nonsinusoidal for a finite transparency. It is demonstrated that even for the nearly fully transparent interfaces the small corrections due to weak interfacial disorders contribute a small second-harmonic component in the current-phase relation. For a certain thicknesses of the ferromagnetic contact and the exchange field this can lead to a tiny minimum supercurrent at the crossover between 0 and $\pi$ states of the junction. Our theory has a satisfactory agreement with the recent experiments in which a finite supercurrent was observed at the transition temperature. We further explain the possibility for observation of a large residual supercurrent if the interfaces have an intermediate transparency.

7 pages, 4 figures

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Cited by in corpus (11)

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• Charge and Spin Currents in Ferromagnetic Josephson junctions
• Spin-triplet Supercurrent through Inhomogeneous Ferromagnetic Trilayers
• Josephson Currents and Spin Transfer Torques in Ballistic SFSFS Nanojunctions
• The role of interface transparency and spin-dependent scattering in diffusive ferromagnet/superconductor heterostructures
• Nonsinusoidal current-phase relation in strongly ferromagnetic and moderately disordered SFS junctions
• Spin supercurrent in Josephson contacts with noncollinear ferromagnets
• Magnetic interference pattern in planar SNS Josephson junctions
• Width of the $0-\pi$ phase transition in diffusive magnetic Josephson junctions