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Finite-size and pressure effects in YBa_2Cu_4O_8 probed by magnetic field penetration depth measurements

R. Khasanov·T. Schneider·J. Karpinski·H. Keller
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Abstract

We explore the combined pressure and finite-size effects on the in-plane penetration depth λ_{ab} in YBa_2Cu_4O_8. Even though this cuprate is stoichiometric the finite-size scaling analysis of λ_{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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R. Khasanov, T. Schneider, J. Karpinski, H. Keller. 2004-02-15. Finite-size and pressure effects in YBa_2Cu_4O_8 probed by magnetic field penetration depth measurements. https://doi.org/10.1103/physrevb.70.144515

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