Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 21: Superconductivity: Poster Session

TT 21.34: Poster

Monday, March 16, 2015, 15:00–18:00, Poster B

Thickness Dependence of the Triplet Spin-Valve Effect in Superconductor-Ferromagnet Heterostructures — •Daniel Lenk¹, Vladimir I. Zdravkov^1,2, Jan Kehrle¹, Günther Obermeier¹, Roman Morari^1,3, Hans-Albrecht Krug von Nidda¹, Claus Müller¹, Anatolie S. Sidorenko³, Siegfried Horn¹, Reinhard Tidecks¹, and Lenar Tagirov⁴ — ¹Institut für Physik, Universität Augsburg, D-86159 Augsburg, Germany — ²Present address: Institut für angewandte Physik, Universität Hamburg, D-20355 Hamburg, Germany — ³D. Ghitsu Institute of Electronic Engineering and Nanotechnologies ASM, MD 2028 Kishinev, Moldova — ⁴Solid State Physics Department, Kazan Federal University, 420008 Kazan, Russia

We investigated the triplet spin-valve effect in nanoscale layered S/F₁/N/F₂/AF heterostructures with varying F₁-layer thickness (where S=Nb is a singlet superconducting, F₁=Cu₄₁Ni₅₉ and F₂=Co a ferromagnetic, and N a normal-conducting, non-magnetic layer). The theory predicts a long-range, odd-in-frequency triplet component of superconductivity at non-collinear alignment of the magnetizations of F₁ and F₂. This triplet component exhausts the singlet state and, thus, lowers the superconducting transition temperature, T_c, yielding a global minimum of T_c close to the perpendicular mutual orientations of the magnetizations. We found an oscillating decay of T_c suppression, due to the generation of the triplet component, with increasing F₁ layer thickness, which we discuss in the framework of recent theories. This work was supported by DFG Grant No. HO955/9-1.