Picosecond electric field pulse induced coherent magnetic switching in MgO/FePt/Pt(001)-based tunnel junctions: a multiscale study

Combined methods of first-principles calculations and Landau-Lifshitz-Gilbert (LLG) macrospin simulations are performed to investigate the coherent magnetization switching in the MgO/FePt/Pt(001)-based magnetic tunnel junctions triggered by short pulses of electric field through the control of magnetic anisotropy energy (MAE) electrically. First-principles calculations indicate that the MAE of MgO/FePt/Pt(001) film varies linearly with the change of the electric field, whereas the LLG simulations show that the change in MAE by electric field pulses could induce the in-plane magnetization reversal of the free layer by tuning the pulse parameters. We find that there exist a critical pulse width tau(min) to switch the in-plane magnetization, and this tau(min) deceases with the increasing pulse amplitude E-0. Besides, the magnetization orientation cannot be switched when the pulse width exceeds a critical value tau(max), and tau(max) increases asymptotically with E-0. In addition, there exist some irregular switching areas at short pulse width due to the high precessional frequency under small initial angle. Finally, a successive magnetization switching can be achieved by a series of electric field pulses.