We shall describe a mechanism explaining recently observed
spin conductance oscillations. A model in which the spin flip
occurs at point impurities will be analyzed. It reproduces
the experimental data - see P. Seba, P. Exner, K.N. Pichugin,
A. Vyhnal, P. Streda: Two-component interference effect:
model of a spin-polarized transport, Phys. Rev. Lett.
86 (2001), 1598-1601.