EFFECTS OF SPIN ACCUMULATION ON SINGLE-ELECTRON TUNNELING IN A DOUBLEFERROMAGNETIC MICROJUNCTION

Electron tunneling in a double microjunction, in which one electrode i s nonmagnetic while the second electrode and metallic island are ferro magnetic, is analysed theoretically in the Coulomb blockade regime. Th e limit of fast intrinsic spin relaxation on the island (no spin accum ulation) is compared with the limit of slow spin relaxation (maximum s pin accumulation). It is shown that spin accumulation leads to a stron g dependence of the Coulomb ''staircase'' on the magnetic configuratio n of the junction and, consequently, to a number of new effects.