Effects of spin relaxation on electron tunneling through single discrete levels in magnetic tunnel junctions

Electron tunneling through a single discrete level of a quantum dot, coupled to two ferromagnetic leads, is studied theoretically in the sequential tunneling regime. Electron correlations and spin relaxation processes on the dot are taken into account. It is shown that strong Coulomb correlations can enhance tunnel magnetoresistance in a certain bias range. The effect, however, is suppressed by spin-flip processes.