Disorder and magnetic field dependence of slow electronic relaxation

We show that the relaxation of the excess conductivity in a hopping system driven far from equilibrium is systematically affected by static disorder and magnetic field. In following the glasslike relaxation for times much longer than has been done before we observe a new time dependence of the relaxation. A positive magnetoresistance and a strong effect of the magnetic field on the relaxation indicate that spins may play an important role in the nonequilibrium properties of such systems.