The role of interface transparency and spin-dependent scattering in diffusive ferromagnet/superconductor heterostructures

Abstract

We present a numerical study of the density of states in a ferromagnet/superconductor junction and the Josephson current in a superconductor/ferromagnet/superconductor junction in the diffusive limit by solving the Usadel equation with Nazarov's boundary conditions. Our calculations are valid for an arbitrary interface transparency and arbitrary spin-dependent scattering rate, which allows us to explore the entire proximity-effect regime. We first investigate how the proximity-induced anomalous Green's function affects the density of states in the ferromagnet for several values of the exchange field. In each case, we consider the effect of the barrier transparency and allow for various concentrations of magnetic impurities. In particular, we address how the zero-energy peak and minigap observed in experiments may be understood in terms of the interplay between the singlet and triplet anomalous Green's function and their dependence on the concentration of magnetic impurities. We also investigate the role of the barrier transparency and spin-flip scattering in a superconductor/ferromagnet/superconductor junction. We suggest that such diffusive Josephson junctions with large residual values of the supercurrent at the 0-$\pi$ transition, where the first harmonic term in the current vanishes, may be used as efficient supercurrent-switching devices. It is also found that uniaxial spin-flip scattering has very different effect on the 0-$\pi$ transition points depending on whether one regards the width- or temperature-dependence of the current.

16 pages, 12 figures. Accepted for publication in Phys. Rev. B. High-resolution figures will be available in published version. Shortened abstract due to arXiv submission

References in corpus (13)

• Half-integer Shapiro steps at the 0-pi crossover of a ferromagnetic Josephson junction
• Manifestation of the odd-frequency spin-triplet pairing state in diffusive ferromagnet / superconductor junctions
• A supercurrent switch in graphene $\pi$-junctions
• Striking properties of Superconductor/Ferromagnet structures with spin-dependent scattering
• Spectroscopy and critical temperature of diffusive superconducting/ferromagnetic hybrid structures with spin-active interfaces
• Superharmonic Josephson relation at 0-/$\pi$-junction transition
• Theory of Josephson effect in unconventional superconducting junctions with diffusive barriers
• Scattering by magnetic and spin-orbit impurities and the Josephson current in superconductor-ferromagnet-superconductor junctions
• Nonsinusoidal current-phase relations and the $0-\pi$ transition in diffusive ferromagnetic Josephson junctions
• Role of magnetic scattering in 0-pi transitions in a superconductor/ferromagnetic metal/superconductor junction
• Nonmonotonic temperature dependence of critical current in diffusive d-wave junctions
• Spin-flip scattering and non-ideal interfaces in dirty ferromagnet/superconductor junctions
• 0-pi transition in SFS junctions with strongly spin-dependent scattering

Cited by in corpus (7)

• Pairing symmetry conversion by spin-active interfaces in superconducting junctions
• Theory of superconducting and magnetic proximity effect in S$\mid$F structures with inhomogeneous magnetization textures and spin-active interfaces
• Josephson current in diffusive multilayer superconductor/ferromagnet/superconductor junctions
• Proximity effect in ferromagnet/superconductor hybrids: from diffusive to ballistic motion
• Effective spin-flip scattering in diffusive superconducting proximity systems with magnetic disorder
• Superconducting/ferromagnetic diffusive bilayer with a spin-active interface: a numerical study
• Width of the $0-\pi$ phase transition in diffusive magnetic Josephson junctions