Flux Pinning Mechanisms in Superconducting A15 Materials and the Optimization of Their Transport Properties

  • D. RodriguesJr.
  • S. Foner
  • D. G. Pinatt
Part of the Advances in Cryogenic Engineering book series (ACRE, volume 44)


The superconducting properties and microscopic characterization are presented for Nb3Sn, (Nb,Ta)3Sn and (Nb,Ti)3Sn conductors made using several different fabrication routes. The element concentration profiles at the grain boundaries, determined using STEM, leads to a pinning model that includes the pinning by normal boundaries and by the grain boundary flux shear. The use of the shear modulus C66 for all the range of field and temperature does not fit the Kramer theory. Use of a flux pinning effective grain size, Deffective, in the model leads to good agreement. Deffective depends on the magnetic field (flux line spacing), has a smooth behavior at high fields and increases almost exponentially at low fields following the flux line spacing behavior, as expected. The determination and optimization of Deffective leads to the best superconductor current carrying characteristics.


Magnetic Field Grain Size Distribution Critical Current Density Flux Line Experimental Behavior 


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Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • D. RodriguesJr.
    • 1
  • S. Foner
    • 2
  • D. G. Pinatt
    • 1
    • 3
  1. 1.Departamento de Engenharia de MateriaisFaculdade de Engenharia Química de LorenaLorenaBrazil
  2. 2.Francis Bitter Magnet LaboratoryMITCambridgeUSA
  3. 3.lnstitute of PhysicsUNICAMPCampinasBrazil

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