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

References in corpus (3)

• Half-integer Shapiro steps at the 0-pi crossover of a ferromagnetic Josephson junction
• Superharmonic Josephson relation at 0-/$\pi$-junction transition
• sin(2 phi) current-phase relation in SFS junctions with decoherence in the ferromagnet

Cited by in corpus (6)

• A supercurrent switch in graphene $\pi$-junctions
• Theory of superconducting and magnetic proximity effect in S$\mid$F structures with inhomogeneous magnetization textures and spin-active interfaces
• 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
• Magnetic interference pattern in planar SNS Josephson junctions
• Width of the $0-\pi$ phase transition in diffusive magnetic Josephson junctions