Dresden 2011 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 46: SC: Tunneling, Josephson Junctions, SQUIDs 1

TT 46.9: Vortrag

Donnerstag, 17. März 2011, 12:45–13:00, HSZ 301

Long-range spin-triplet proximity effect in Josephson junctions with multilayered ferromagnets — •Luka Trifunovic^1,2 and Zoran Radovic¹ — ¹Department of Physics, University of Belgrade, Serbia — ²Department of Physics, University of Basel, Switzerland

We study theoretically the Josephson effect and pairing correlations in planar SF₁F₂S junctions that consist of conventional superconductors (S) connected through two metallic monodomain ferromagnets (F₁ and F₂) with transparent interfaces. We solve self-consistently the Eilenberger equations for arbitrary orientation of in-plane magnetizations in the clean limit and for moderate disorder in ferromagnets. Both singlet and triplet pair amplitudes and the Josephson current-phase relations are calculated numerically. It is shown that for equally thick ferromagnetic layers (symmetric junctions) the long-range spin-triplet correlations are not dominant: For thin ferromagnetic layers all amplitudes are equally large, while for thick layers the long range triplet amplitude is very small. It is shown that for noncollinear magnetizations the long-range proximity effect can be dominant in highly non-symmetric SF₁F₂S junctions with particularly thin F₁ and thick F₂ ferromagnetic layers. We find that dominant triplet correlations in Josephson junctions with ferromagnetic bilayer always give dominant second harmonics in current-phase relations at low temperatures.