Orientation dependence of the andreev transport in d-wave superconductor-ferromagnet-d-wave superconductor trilayers

Abstract

The quasiparticle transport through ballistic voltage-biased d-wave superconductor- ferromagnet-d-wave superconductor (DFD) junctions with misoriented superconducting electrodes is studied theoretically. We found that at low bias the coherence in the quasiparticle transport could be enhanced by the magnetic field in F. This new feature originates from the interplay between the phase-coherent propagation of Andreev pairs in the barrier and decoherence mechanisms due to the electrode misorientation θ, the presence of the exchange field h in F, the bias voltage, and the temperature. For θ = π/4, where the proximity effect is strongest, there is a distinct enhancement of the current I (h), starting from h = 0 up to a maximum at h ≈ δ(T ). For other misorientations, a similar increase of the current appears only for thin F barriers, or for large enough θ, where the proximity effect is also strong.