  We investigate spin and charge current through a quantum dot pumped by a
time-varying magnetic field. Using the density matrix method, quantum rate
equations for the electronic occupation numbers in the quantum dot are obtained
and solved in the stationary state limit for a wide set of setup parameters.
Both charge and spin current are expressed explicitly in terms of several
relevant parameters and analyzed in detail. The results suggest a way of
optimizing experimental setup parameters to obtain an maximal spin current
without the charge current flow.
