TY  - JOUR
AU  - Khaydukov, Yury
AU  - Pütter, Sabine
AU  - Guasco, Laura
AU  - Morari, Roman
AU  - Kim, Gideok
AU  - Keller, Thomas
AU  - Sidorenko, Anatolie
AU  - Keimer, Bernhard
TI  - Proximity effect in [Nb(1.5 nm)/Fe( x )]$_{10}$ /Nb(50 nm) superconductor/ferromagnet heterostructures
JO  - Beilstein journal of nanotechnology
VL  - 11
SN  - 2190-4286
CY  - Frankfurt, M.
PB  - Beilstein-Institut zur Förderung der Chemischen Wissenschaften
M1  - FZJ-2020-02997
SP  - 1254 - 1263
PY  - 2020
AB  - 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.
LB  - PUB:(DE-HGF)16
C6  - pmid:32874825
UR  - <Go to ISI:>//WOS:000567855800001
DO  - DOI:10.3762/bjnano.11.109
UR  - https://juser.fz-juelich.de/record/878679
ER  -