Analytical solution for precessional magnetization switching in exchange biased high perpendicular anisotropy nanostructures

We analyse the precessional magnetization switching of high perpendicular anisotropy nanostructures biased with an in-plane exchange field. Our calculation is made in the limit of non-damped macrospin ferromagnetic media. From the Landau-Lifshitz-Gilbert equation, we first derive the magnetic trajectories. Then, we give the analytical expressions of the time-dependent magnetization, the precession frequency and the switching time for any in-plane applied field pulse orientation. We show that the exchange bias field decreases significantly both the switching time and the reversal field. We find that the switching time is slightly dependent on the applied field orientation. Typical switching times less than 100 ps are predicted for a Co/Pt multilayer.