Critical current oscillations in strong ferromagnetic pi junctions

J. W. A. Robinson*, S. Piano, G. Burnell, C. Bell, M. G. Blamire, Chris Bell

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

164 Citations (Scopus)

Abstract

We report magnetic and electrical measurements of Nb Josephson junctions with strongly ferromagnetic barriers of Co, Ni, and Ni80Fe20 (Py). All these materials show multiple oscillations of critical current with a barrier thickness implying repeated 0-pi phase transitions in the superconducting order parameter. We show, in particular, that the Co barrier devices can be accurately modeled using existing clean limit theories and that, despite the high exchange energy (309 meV), the large IcRN value in the pi state means Co barriers are ideally suited to the practical development of superconducting pi-shift devices.

Original languageEnglish
Article number177003
Number of pages4
JournalPhysical Review Letters
Volume97
Issue number17
DOIs
Publication statusPublished - 27 Oct 2006

Keywords

  • SUPERCONDUCTING TRANSITION-TEMPERATURE
  • DEAD LAYERS
  • NB-CO
  • MULTILAYERS
  • THICKNESS
  • FILMS
  • METAL
  • TOP

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