Berlin 2005 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

TT: Tiefe Temperaturen

TT 23: Posters Superconductivity, Solids at Low Temperature

TT 23.52: Poster

Monday, March 7, 2005, 14:00–18:00, Poster TU D

Superconductivity in Pd films on Eu_xSr_1−xS — •A. Cosceev^1,2, A. Faißt¹, C. Pfleiderer¹, C. Sürgers^1,2, and H. v. Löhneysen^1,2,3 — 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 d_Pd = 5 - 20 nm) deposited on insulating Eu_xSr_1−xS. Samples have been prepared at different substrate temperatures T_S on 50-nm thick Eu_xSr_1−xS films on Si(111). For films with d_Pd ≤ 7 nm prepared at T_S = 300 K a maximum T_c = 0.9 K is observed for x = 0, i.e. on nonmagnetic SrS. T_c decreases to 0.7 K for x = 0.6 possibly due to the contact with the magnetic insulator. For larger d_Pd, superconductivity is suppressed towards lower T which suggests that the superconducting phase is only stabilized in a narrow region near the Pd/Eu_xSr_1−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)