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The Anisotropy of the Static Magnetic Field Penetration Depth in Superconducting Tin

  • P. C. L. Tai
  • M. R. Beasley
  • M. Tinkham

Abstract

The magnetic field penetration depth λ of superconductors has been measured in the past by various radiofrequency and microwave techniques or by using small colloidal samples. In this paper we describe a new method, which we have successfully applied to tin, for directly measuring the temperature dependence of λ at dc and on macroscopic, oriented single crystals. The method utilizes the extremely high flux sensitivity of a SQUID magnetometer to measure the flux penetrating into a superconductor in a low (~ 1 Oe) static magnetic field. With this technique changes in λ as small as 2 Å can be resolved. Moreover, flat, planar samples have been used so that both the direction of the shielding current J and the normal \(\hat{n}\) to the sample surface can be directed along well-defined crystallographic directions. The temperature dependence of λ is found to depend on both Ĵ and \(\hat{n}\). While a dependence on Ĵ has been observed previously, the dependence on \(\hat{n}\) has not. As described below, both types of anisotropy can be understood on the basis of Pippard’s nonlocal theory1 of electrodynamics.

Keywords

Fractional Anisotropy Fermi Surface Squid Magnetometer Microwave Technique Oriented Single Crystal 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    A.B. Pippard, Proc. Roy. Soc. (London) A216, 547 (1953).ADSCrossRefGoogle Scholar
  2. 2.
    P.B. Miller, Phys. Rev. 113, 1209 (1959).ADSCrossRefGoogle Scholar
  3. 3.
    J.R. Waldram, Adv. Phys. 13, 1 (1964).ADSCrossRefGoogle Scholar
  4. 4.
    A.B. Pippard, Proc. Roy. Soc. (London) A224, 278 (1954).Google Scholar

Copyright information

© Springer Science+Business Media New York 1974

Authors and Affiliations

  • P. C. L. Tai
    • 1
  • M. R. Beasley
    • 1
  • M. Tinkham
    • 1
  1. 1.Harvard UniversityCambridgeUSA

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