Sign reversal of ac Josephson current in a ferromagnetic Josephson junction

Shin Ichi Hikino, Michiyasu Mori, Saburo Takahashi, Sadamichi Maekawa

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3 Citations (Scopus)


The ac Josephson effect in a ferromagnetic Josephson junction, which is composed of two superconductors separated by a ferromagnetic metal (FM), is studied by a tunneling Hamiltonian and Green's function method. We obtain two types of superconducting phase dependent currents, i.e., Josephson current and quasiparticle-pair-interference current (QPIC). These currents change their signs with thickness of the FM layer due to the 0-π transition characteristic to the ferromagnetic Josephson junction. As a function of applied voltage, the Josephson critical current shows a logarithmic divergence called the Riedel peak at the gap voltage, while the QPIC shows a discontinuous jump. The Riedel peak reverses due to the 0-π transition and disappears near the 0-π transition point. The discontinuous jump in the QPIC also represents similar behaviors to the Riedel peak. These results are in contrast to the conventional ones.

Original languageEnglish
Article number014708
Journaljournal of the physical society of japan
Issue number1
Publication statusPublished - 2009 Jan


  • 0-state
  • Ac Josephson effect
  • Ferromagnet
  • Ferromagnetic Josephson junction
  • Pi-state
  • Riedel peak
  • Superconductor

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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