Spin accumulation and cotunneling effects in ferromagnetic single-electron transistors

Electron tunneling through small metallic particles (islands) coupled to two ferromagnetic electrodes is studied theoretically in the Coulomb blockade regime, where higher order tunneling processes play a significant role. Transport characteristics of the system are analyzed by the real-time diagrammatic technique. It is shown that the spin splitting of the electrochemical potential due to spin accumulation on the island should be detectable from the spacing between two resonances in the current-voltage characteristics. (C) 2002 Elsevier Science B,V. All rights reserved.