Abstract
We study a diffusive superconductor-ferromagnet-superconductor (SFS) junction with in-plane ferromagnetic domains. Close to the superconducting transition temperature, we describe the proximity effect in the junction with the linearized Usadel equations [Phys. Rev. Lett. 25, 507 (1970)]. We find that properties of such a junction depend on the size of the domains relative to the magnetic coherence length. In the case of large domains, the junction exhibits transitions to the state, similar to a single-domain SFS junction. In the case of small domains, the magnetization effectively averages out, and the junction is always in the zero state, similar to a superconductor-normal metal-superconductor junction. In both those regimes, the influence of domain walls may be approximately described as an effective spin-flip scattering. We also study the inhomogeneous distribution of the local current density in the junction. Close to the transitions, the directions of the critical current may be opposite in the vicinity of the domain wall and in the middle of the domains.
- Received 13 June 2007
DOI:https://doi.org/10.1103/PhysRevB.76.134502
©2007 American Physical Society