Magnetoresistance of ferromagnetic single-electron transistors

We investigate the magnetoresistance of the single-electron transistor made of ferromagnetic leads and island. By lowering the temperature, the Coulomb blockade of the single electron tunneling is enhanced, which in turn influences the magnetoresistance of the device. The corresponding magnetoresistance ratio as a function of the temperature is studied by taking into account both the spin-dependent tunneling processes and the Coulomb blockade effect. Finally, we determine the parameter range, in which the ferromagnetic single-electron transistor can be used as a device with the magnetoresistance ratio enhanced by the Coulomb blockade effect. (C) 2000 American Institute of Physics. [S0003-6951(00)04449-1].