  Field-free switching of perpendicularly magnetized ferromagnetic layer by
spin orbit torque (SOT) from the spin Hall effect (SHE) is of great interest in
the applications of magnetic memory devices. In this paper, we investigate the
deterministic SOT switching through the joint effects of Dzyaloshinskii-Moriya
Interaction (DMI) and field-like torque (FLT) by micromagnetic simulations. We
confirmed that within a certain range of DMI values and charge current
densities, it is possible to deterministically switch the magnetization without
the assistance external magnetic field. We show that the FLT could play an
adverse role in blocking and slowing down the magnetization switching under
certain cases of DMI and charge current-driven field-free switching. However,
in other cases, FLT can assist DMI on the deterministic field-free SOT
switching. In addition, it is found that FLT can effectively expand the current
density window for a deterministic field-free SOT switching in the presence of
DMI.
