Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 9: SC: Poster Session
TT 9.52: Poster
Montag, 22. März 2010, 14:00–18:00, Poster A
Ferromagnet-superconductor hybrids with perpendicular magnetization: current-perpendicular-to-plane measurements — •Richard Montbrun1, Christoph Sürgers1, and Hilbert v. Löhneysen1,2 — 1Karlsruher Institut für Technologie, Physikalisches Institut, D-76131 Karlsruhe — 2Karlsruher Institut für Technologie, Institut für Festkörperphysik, D-76131 Karlsruhe
Ferromagnet (F)/superconductor (S)/F hybrid structures - with S = Nb and Co/Pt multilayers as F electrodes - were fabricated by e-beam lithography and reactive ion-etching using silicon-nitride shadow masks on Si/SiO2. The perpendicular magnetization of the F electrodes was confirmed by measurements of the anomalous Hall effect. The sample layout was developed to allow for four-point resistivity measurements with the current perpendicular to the F/S interface. In the normal state (temperature T = 10 K) the magnetoresistance R(H) shows a spin-valve effect due to the different coercivities of the top and bottom F electrode arising from different Co-layer thicknesses and deposition temperatures. At lower temperatures we investigate the resistance R(H,T) of the superconducting spin-valve for different S-layer thicknesses and transport currents. Preliminary data demonstrate a current dependence of the transition temperature Tc in the magnetically saturated state but only a minor influence of the relative orientation of the two F-layer magnetizations on Tc. Effects of the magnetic stray fields arising from the nanostructured F electrodes and the spin-dependent scattering on the superconducting properties are discussed.