  Spin orbit torque (SOT) has been considered as one of the promising
technologies for the next-generation magnetic random access memory (MRAM). So
far, SOT has been widely utilized for inducing various modes of magnetization
switching. However, it is challenging to integrate multiple modes of
magnetization switching together. In this work we propose a method for
implementing both unipolar and bipolar switching of the perpendicular
magnetization within a single SOT device. The mode of switching could be easily
altered by tuning the amplitude of the applied current. We show that the
field-like torque plays an important role in the switching process. The
field-like torque induces the precession of the magnetization in the case of
unipolar switching, whereas it helps to generate an effective z-component
torque in the case of bipolar switching. In addition, the influence of key
parameters on the mode of switching is discussed. Our proposal could be used to
design novel reconfigurable logic circuits in the near future.
