Local and Global measurements of London Penetration Depth in Inhomogeneous Superconductors

ORAL

Abstract

An important parameter, the London penetration depth (LPD), in superconductors can be estimated from the global (whole sample) response [1] or measuring the first critical field locally near the surface [2]. We compare LPD from the global tunnel diode resonator (TDR) technique [1] with the local values obtained by using NV-centers in diamond optical magnetometry [2]. We deliberately chose a crystal of Ba(Fe1-xCox)2As2 pnictide superconductor that looks like an old book under an electron microscope, revealing a peculiar planar stack-like structure. We also examined a standard single crystal of YBa2Cu3O7-δ. While the temperature dependence of LPD is the same between TDR and NV-centers magnetometry, the absolute values differ by a factor of two in FeCo122, but are practically the same in YBCO. We model this situation numerically by finite-element method solving the London equations for our particular sample geometry and find unobvious behavior apparently due to the non-local long-range electromagnetic behavior of the finite-sized superconductor in an external field.
[1] R. Prozorov and R. W. Giannetta, SUST 19, R41 (2006)
[2] K. R. Joshi et al. PRApp. 11, 014035 (2019).

*Supported by the US DOE, Office of Science, BES MSED under contract # DE-AC02-07CH11358.

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Presenters

  • Kamal Joshi

    • Ames Laboratory, Ames, IA

Authors

  • Kamal Joshi

    • Ames Laboratory, Ames, IA

  • William S. Setterberg

    • Macalester College, Saint Paul, MN

  • Naufer M Nusran

    • Ames Laboratory, Ames, IA

  • Sunil Ghimire

    • Iowa State University
    • Ames Laboratory, Ames, IA
    • Ames Laboratory

  • Kyuil Cho

    • Ames Laboratory
    • Ames Laboratory, Ames, IA

  • Makariy Tanatar

    • Ames Laboratory
    • Ames Laboratory, Ames, IA
    • Ames Lab

  • Sergey Budko

    • Iowa State University/ Ames Laboratory
    • Ames Laboratory
    • Physics and Astronomy, Iowa State University/Ames Laboratory
    • Ames Laboratory/Iowa State University
    • Ames Lab/Iowa State
    • Ames Laboratory, Ames, IA
    • Iowa State University/AmesLab
    • Department of Physics & Astronomy, Iowa State University/Ames Laboratory

  • Paul C Canfield

    • Iowa State University/ Ames Laboratory
    • Ames Laboratory
    • Ames Laboratory, Iowa State University
    • Iowa State University
    • Ames Lab/Iowa State
    • Ames Laboratory, Ames, IA
    • Iowa State University/AmesLab
    • Department of Physics and Astronomy, Iowa State University/Ames Laboratory
    • Department of Physics & Astronomy, Iowa State University/Ames Laboratory
    • Ames Laboratory, U.S. Department of Energy, and Department of Physics and Astronomy, Iowa State University
    • Ames Laboratory/Iowa State University

  • Ruslan Prozorov

    • Iowa State University
    • Ames Laboratory, Ames, IA
    • Department of Physics and Astronomy, Iowa State University
    • Ames Laboratory
    • Ames Laboratory/Iowa State University
    • Ames Lab