Subnanosecond switching of local spin-exchange coupled to ferromagnets

The dynamics of a single spin that is embedded in a tunnel junction between ferromagnetic contacts is strongly affected by the exchange coupling to the tunneling electrons, By using time-dependent equations of motion for the spin, which is under the influence of a spin-polarized tunneling current, it is shown that the magnetic field induced by bias voltage pulses allows for a subnanosecond switching of the local spin and the possibility of spin reversal is illustrated. Furthermore, it is shown that the time evolution of the Larmor frequency sharply peaks around the spin-flip event and it is argued that this feature can be used as an indicator for the spin flip.