  The tunneling through a ferromagnet/normal metal/ferromagnet double junction
in the Coulomb blockade regime is studied, assuming that the spin relaxation
time of electron in the central metallic island is sufficiently large. Using
the master equation, the current, the tunnel magnetoresistance (TMR), and the
current noise spectrum have been calculated for devices of different
parameters. It was shown that the interplay between spin and charge
correlations strongly depends on the asymmetry of measured device. The charge
correlation makes both the chemical potential shift, which describes the spin
accumulation in the central island, and the TMR oscillated with the same period
as the Coulomb staircase in current-voltage characteristics. This effect is
smeared by the temperature. The spin correlation may cause an enhancement of
noise at finite frequencies, while the zero frequency noise is still always
sub-poissonian. The gate voltage causes an oscillation of not only conductance,
but also TMR and noise.
