Subnanosecond switching of local spin-exchange coupled to ferromagnets

The dynamics of a single spin embedded in a the tunnel junction between ferromagnetic contacts is strongly affected by the exchange coupling to the tunneling electrons. Using time-dependent equation of motion for the spin under influence of the spin-polarized tunneling current, it is shown that the magnetic field induced by bias voltage pulses allows for sub-nanosecond 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.