Self-frustrated arrays of small pi, Greek-junctions and 0–small pi, Greek-bi-stability

V. V. RyazanovCorresponding Author Contact Information, E-mail The Corresponding Author, V. A. Oboznov, A. V. Timofeev and V. V. Bol'ginov

Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka 142432, Russia

Available online 14 June 2003.


Phase interference in arrays of superconductor–ferromagnet–superconductor (SFS) Josephson junctions has been investigated experimentally. A transition of the SFS junctions to the small pi, Greek-state manifests itself in the half-period shift of the external magnetic field dependence of the transport critical current in the triangular SFS arrays. It is associated with the appearance of spontaneous supercurrents in the array at zero external field, with the ground state degenerated with respect to the two possible current flow directions. In conventional Josephson arrays this state can be observed only by imposing frustrating external field equal to a half-integer number of magnetic quanta per cell. At temperatures close to the `0–small pi, Greek' transition the critical current versus field dependences of the arrays have shown the behaviour that can been explained by 0–small pi, Greek-bi-stability of the SFS junctions.

Author Keywords: Superconducting multilayered structures; Heterojunctions; SFS junctions; small pi, Greek-Junctions; Self-frustrated Josephson junction arrays

Corresponding Author Contact InformationCorresponding author.