Berlin 2005 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 23: Posters Superconductivity, Solids at Low Temperature
TT 23.52: Poster
Montag, 7. März 2005, 14:00–18:00, Poster TU D
Superconductivity in Pd films on EuxSr1−xS — •A. Cosceev1,2, A. Faißt1, C. Pfleiderer1, C. Sürgers1,2, and H. v. Löhneysen1,2,3 — 1Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe, Germany — 2DFG Center for Functional Nanostructures (CFN), Universität Karlsruhe, D-76128 Karlsruhe, Germany — 3Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe, Germany
Superconductivity in Pd was reported earlier for He+-irradiated films [1] and for Ag/Pd/Ag sandwiches [2]. Here we investigate the effect of ferromagnetic order on the superconductivity of Pd films (thickness dPd = 5 - 20 nm) deposited on insulating EuxSr1−xS. Samples have been prepared at different substrate temperatures TS on 50-nm thick EuxSr1−xS films on Si(111). For films with dPd ≤ 7 nm prepared at TS = 300 K a maximum Tc = 0.9 K is observed for x = 0, i.e. on nonmagnetic SrS. Tc decreases to 0.7 K for x = 0.6 possibly due to the contact with the magnetic insulator. For larger dPd, superconductivity is suppressed towards lower T which suggests that the superconducting phase is only stabilized in a narrow region near the Pd/EuxSr1−xS interface. Application of a magnetic field clearly shows the gradual transition towards insulating behavior as seen by a logarthmic increase of the resistance R with decreasing temperature T. The magnetoresistance is positive up to a maximum field of 18 T supporting the presence of strong electron-electron interaction effects.
[1] B. Stritzker, Phys. Rev. Lett. 42, 1769 (1979)
[2] M. B. Brodsky, Phys. Rev. B 25, 6060 (1982)