%0 Journal Article
%A Khaydukov, Yury
%A Pütter, Sabine
%A Guasco, Laura
%A Morari, Roman
%A Kim, Gideok
%A Keller, Thomas
%A Sidorenko, Anatolie
%A Keimer, Bernhard
%T Proximity effect in [Nb(1.5 nm)/Fe( x )]$_{10}$ /Nb(50 nm) superconductor/ferromagnet heterostructures
%J Beilstein journal of nanotechnology
%V 11
%@ 2190-4286
%C Frankfurt, M.
%I Beilstein-Institut zur Förderung der Chemischen Wissenschaften
%M FZJ-2020-02997
%P 1254 - 1263
%D 2020
%X We have investigated the structural, magnetic and superconduction properties of [Nb(1.5 nm)/Fe(x)]$_{10}$ superlattices deposited on a thick Nb(50 nm) layer. Our investigation showed that the Nb(50 nm) layer grows epitaxially at 800 °C on the Al2O3(1$\bar{1}$02) substrate. Samples grown at this condition possess a high residual resistivity ratio of 15–20. By using neutron reflectometry we show that Fe/Nb superlattices with x < 4 nm form a depth-modulated FeNb alloy with concentration of iron varying between 60% and 90%. This alloy has weak ferromagnetic properties. The proximity of this weak ferromagnetic layer to a thick superconductor leads to an intermediate phase that is characterized by a suppressed but still finite resistance of structure in a temperature interval of about 1 K below the superconducting transition of thick Nb. By increasing the thickness of the Fe layer to x = 4 nm the intermediate phase disappears. We attribute the intermediate state to proximity induced non-homogeneous superconductivity in the structure.
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:32874825
%U <Go to ISI:>//WOS:000567855800001
%R 10.3762/bjnano.11.109
%U https://juser.fz-juelich.de/record/878679