We calculated here a magnetostatic energy and domain structure in a long enough ferromagnetic layer having final width and parallel anisotropy so that magnetization vectors in domains lie in plane – the so called “Cotton-type” domains. As appears the period of such a domain structure is proportional to the layer width and to domain wall energy but inversely proportional to magnetization squared. In an external magnetic field the width of the preferential domains rises but the domain boundaries do not escape – very narrow unpreferential domains form 360-degree domain walls. On the base of a phenomenological theory we considered then a model of a three layer magnetic junction, consisting of two ferromagnetic layers (electrodes) separated by a non-magnetic ultrathin layer (spacer). One of the electrodes has a magnetization pinned parallel to interfaces along z-axis and the other one is free and may contain a “Cotton-type” magnetic domain structure. An electrical current may be present that transports carries through the spacer from the pinned layer to the free one. No spin-dependent surface scattering exists and current effects on the magnetic state of the free layer due to injection of the spins only. We found a solution of continuity equations for carriers having up and down spins that satisfy boundary conditions at interfaces of the free electrode. Current dependent density and magnetization of the injected spins were calculated. This allows us to find the current dependent energy of exchange interaction between carriers and localized spins (s-d interaction). From the condition that a total magnetic energy of the junction should be minimal we found a period W of a domain structure and a relative width of a preferential domain as a function of some "driving parameter" f containing external magnetic field H and spin polarized current density j. Mutual cancellation may be possible of field and current actions. Let field H is large enough to saturate free electrode opposite to z-axis i.e. to the magnetization of the pinned electrode. Then our calculations show the possibility of magnetization reversal of the free electrode under the currents densities of the order ~100000 A per 1cm squared. This work was supported by ISTC (grant #1522) and by RFBR (grant # 00-02-16384).