Superconducting state of very thin Pd films deposited on a diluted insulating EuxSr1−xS ferromagnet

Abstract

The electronic transport in very thin Pd films deposited on insulating EuxSr1−xS (0⩽x⩽1) is investigated. The temperature dependent resistance R(T) of films with dPd⩾14 nm shows metallic behavior and a logarithmic increase toward low temperatures characteristic of (anti-)localization and electron-electron interaction effects also observed for Pd films on Si(111). Films with dPd=7 nm are superconducting below a transition temperature Tc which decreases with increasing Eu concentration from Tc=0.9 K for x=0 to Tc<50 mK for x=1. The origin of superconductivity in the thin Pd films is presumably due to the formation of an interfacial Pd-S alloy and/or to a charge transfer at the Pd/EuxSr1−xS interface. The decrease of Tc vs x is attributed to the magnetic pair breaking of the ferromagnetic EuxSr1−xS underneath. The R(T) behavior of films with dPd⩾10 nm suggests that these are not superconducting or have a strongly reduced Tc presumably due to the proximity effect of the nonsuperconducting S-free upper part of the Pd film.

Source-reported materials — not catalogue approval

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