Non-uniform superconductivity in S/F nanostructures

Abstract
A strong exchange field acting on the Cooper pairs in the ferromagnetic (F) metal leads to the damping oscillatory behaviour of the superconducting order parameter inside the F layer. In consequence the electron density of state and spin polarization decay non-monotonously in S/F proximity structures. We review the influence of these effects on the properties of S-F multilayers where the critical temperature and Josephson current depend in an oscillatory manner on the exchange field and thickness of ferromagnetic metal. These oscillations are related with the transition into the state where the phase of superconducting order parameter is opposite on the adjacent superconducting layers. We briefly discuss the properties of the Josephson junction at this transition.