Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Finite-size and pressure effects in YBa_2Cu_4O_8 probed by magnetic
  field penetration depth measurements   We explore the combined pressure and finite-size effects on the in-plane
penetration depth \lambda_{ab} in YBa_2Cu_4O_8. Even though this cuprate is
stoichiometric the finite-size scaling analysis of \lambda_{ab}^{-2}(T)
uncovers the granular nature and reveals domains with nanoscale size L_{c}
along the c-axis. L_{c} ranges from 33.2 Angstrom to 28.9 Angstrom at pressures
from 0.5 to 11.5 kbar. These observations raise serious doubts on the existence
of a phase coherent macroscopic superconducting state in cuprate
superconductors.

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The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
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The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org