Josephson effect in superconductor/ferromagnet-normal/superconductor structures

Abstract

The critical current I C of superconductor/ferromagnet-normal/superconductor ͑S/FN/S͒ Josephson junctions is calculated in the framework of linearized Usadel equations. The dependence of I C on the distance L between superconductors and thicknesses d F,N of ferromagnetic and normal layers is analyzed. It is shown that I C ͑L , d F ͒ may exhibit damping oscillations as a function of both arguments. The conditions have been determined under which the decay length and period of oscillation of I C ͑L͒ at fixed d F are on the order of decay length of superconducting correlations in the N metal, N , that is much larger than in F film. We demonstrate also that the positions of the points L = L n , at which I C = 0 exhibit damping oscillations as a function of d F . The number of transitions from 0 to states in I C ͑L , d F ͒ increases under L → L n . Outside these narrow intervals of L around L n sign and value of I C are independent on d F for d F տ F .

Josephson φ-junctions based on structures with complex normal/ferromagnet bilayer

“…In general, there are three characteristic decay lengths in the considered structure 44,47,68 . They are ξ N , ξ H = ξ 1 + iξ 2 , and ζ = ζ 1 + iζ 2 .…”

“…(9a), (9b) is a normal vector directed into material marked at derivative. For the structure presented in Fig.1a, the boundary-value problem (4) -(9b) was solved analytically in the linear approximation 47,48 , i.e. under conditions…”

Controllable proximity effect in superconducting hybrid devices

“…It was suggested recently in [47] − [49] to fabricate the "current in plane" SFS devices having the weak link region consisting from NF or FNF multilayers with the supercurrent owing parallel to FN interfaces. In these structures, superconductivity is induced from the S banks into the normal (N) lm, while F lms serves as a source of spin polarized electrons, which diuse from F to N layer thus providing an eective exchange eld in a weak link.…”

“…In general case, there are three characteristic decay lengths in the considered structure [47] , [47] , [68]. They are ξ N , ξ H = ξ 1 + iξ 2 , and ζ = ζ 1 + iζ 2 .…”

“…(1.9a), (1.9b) is a normal vector directed into material marked at derivative. For the structure presented in Fig.1.1a, the boundary-value problem (1.4) -(1.9b) was solved analytically in the linear approximation [47,48], i.e. under conditions…”