Spin-accumulation in small ferromagnetic double barrier junctions
  The non-equilibrium spin accumulation in ferromagnetic double barrier junctions is shown to govern the transport in small structures. Transport properties of such systems are described by a generalization of the theory of the Coulomb blockade. The spin accumulation enhances the magnetoresistance. The transient non-linear transport properties are predicted to provide a unique experimental evidence of the spin-accumulation in the form of a reversed current on time scales of the order of the spin-flip relaxation time. 
Arne Brataas, Yu. V. Nazarov, J. Inoue and Gerrit E.W. Bauer