Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Meissner response of a bulk superconductor with an embedded sheet of
  reduced penetration depth   We calculate the change in susceptibility resulting from a thin sheet with
reduced penetration depth embedded perpendicular to the surface of an isotropic
superconductor, in a geometry applicable to scanning Superconducting QUantum
Interference Device (SQUID) microscopy, by numerically solving Maxwell's and
London's equations using the finite element method. The predicted stripes in
susceptibility agree well in shape with the observations of Kalisky et al. of
enhanced susceptibility above twin planes in the underdoped pnictide
superconductor Ba(Fe1-xCox)2As2 (Ba-122). By comparing the predicted stripe
amplitudes with experiment and using the London relation between penetration
depth and superfluid density, we estimate the enhanced Cooper pair density on
the twin planes, and the barrier force for a vortex to cross a twin plane. Fits
to the observed temperature dependence of the stripe amplitude suggest that the
twin planes have a higher critical temperature than the bulk, although stripes
are not observed above the bulk critical temperature.

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The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys