Interference phenomena and long - range proximity effect in clean   superconductor -- ferromagnet systems
  We study peculiarities of proximity effect in clean superconductor -- ferromagnet structures caused by either spatial or momentum dependence of the exchange field. Even a small modulation of the exchange field along the quasiparticle trajectories is shown to provide a long range contribution to the supercurrent due to the specific interference of particle- and hole- like wave functions. The momentum dependence of the exchange field caused by the spin -- orbit interaction results in the long -- range superconducting correlations even in the absence of ferromagnetic domain structure and can explain the recent experiments on ferromagnetic nanowires. 
A. S. Mel'nikov, A. V. Samokhvalov, S. M. Kuznetsova, A. I. Buzdin
cond-mat.supr-con