The effect of the spin accumulation on the spin-dependent transport properties in a ferromagnet–quantum dot (QD)–ferromagnet tunnel junction is reexamined in a self-consistent manner by means of Keldysh nonequilibrium Green function method. It has been found that when the spin and charge densities accumulated in the central QD are self-consistently treated, the electrical current and spin current differ from the previous results where the chemical potential shifts induced by the spin imbalance are not included, and the tunnel magnetoresistance is enhanced remarkably. The spin and charge accumulations in the QD are also discussed.

PACS: 75.47.m; 73.63.Kv; 75.70.Cn