Josephson current in diffusive multilayer superconductor/ferromagnet/superconductor junctions

Iver B. Sperstad; Jacob Linder; Asle Sudbø

doi:10.1103/PhysRevB.78.104509

← Back to search

Josephson current in diffusive multilayer superconductor/ferromagnet/superconductor junctions

Iver B. Sperstad, Jacob Linder, Asle Sudbø

DOI 10.1103/PhysRevB.78.104509 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

We calculate the Josephson current in a diffusive superconductor/ferromagnet/superconductor junction, where the ferromagnetic region contains multiple layers (or domains). In particular, we study a configuration where there are two layers with an arbitrary relative in-plane magnetization orientation and also include nonideal interfaces and arbitrary spin-flip scattering. We study the 0−π oscillations of the critical current for varying junction width d and find that the π state vanishes entirely when the magnetic misorientation angle of the two layers exceeds a critical angle ϕc. While ϕc→π/2 in the limit of high temperatures, we find that ϕc becomes smaller than π/2 at low temperatures compared to Tc. 0−π oscillations are also found when varying the temperature or the misorientation angle for fixed values of d, and we present phase diagrams that show qualitatively the conditions for the appearance of such oscillations. We also point out how one may obtain significant enhancement of the critical current in such a system by switching the magnetization for selected values of the junction width d, and comment on the necessary conditions for establishing a long-range triplet Josephson effect.