Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Proximity effect in [Nb(1.5nm)/Fe(x)]$_{10}$/Nb(50nm)
  superconducting/ferromagnet heterostructures   We have investigated the structural, magnetic and superconducting properties
of [Nb(1.5nm)/Fe(x)]$_{10}$ superlattices deposited on a thick Nb(50nm) layer.
Our investigation showed that the Nb(50nm) layer grows epitaxially at
800$^\circ$C on Al$_2$O$_3$(1$\bar{1}$02) substrate. Samples grown at this
condition posses 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 properties of a weak ferromagnet. Proximity of this weak
ferromagnetic layer to a thick superconductor leads to an intermediate phase
that is characterized by co-existing superconducting and normal-state domains.
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 periodic Fe/Nb structure.

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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: cs
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The categories of this paper are: math
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: astro-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: supr-con
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The categories of this paper are: econ
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The categories of this paper are: nlin
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The categories of this paper are: q-fin