Optimal protocol for spin-orbit torque switching of a perpendicular nanomagnet

It is demonstrated by means of the optimal control theory that energy cost spin-orbit torque induced reversal a nanomagnet with perpendicular anisotropy can be strongly reduced proper shaping both in-plane components current pulse. The time-dependence switching pulse minimizes associated Joule heating derived analytically in terms required time and material properties. providing tradeoff between speed efficiency obtained. A sweet-spot balance field-like damping-like discovered; it permits for particularly efficient down-chirped rotating whose duration does not need to adjusted precisely.