  Spin dependent single electron tunneling in a ferromagnetic double junction
is investigated theoretically in the limit of incoherent sequential tunneling.
The junction consists of a small nonmagnetic metallic grain with discrete
energy levels, which is connected to two ferromagnetic electrodes. We have
developed a new theoretical model taking into account charge as well as spin
degrees of freedom. The model allows us to investigate new phenomena such as
spin accumulation and spin fluctuations.
