  We theoretically study electronic transport through a layer of quantum dots
connecting two metallic leads. By the inclusion of an inductor in series with
the junction, we show that steady electronic transport in such a system may be
unstable with respect to temporal oscillations caused by an interplay between
the Coulomb blockade of tunneling and spin accumulation in the dots. When this
instability occurs, a new stable regime is reached, where the average spin and
charge in the dots oscillate periodically in time. The frequency of these
oscillations is typically of the order of 1GHz for realistic values of the
junction parameters.
