Effect of the field-like spin torque on the switching current and switching speed of magnetic tunnel junction with perpendicularly magnetized free layers

摘要

We have studied the effect of the fieldlike spin torque term bj, present in magnetic tunneling junctions (MTJs) with perpendicular magnetic anisotropy in the free layer, on switching characteristics of the devices. We find that bj has a strong impact on the switching current density and switching speed. The theoretical limit of the switching current density can be significantly reduced and the theoretical limit of the switching time will be lowered compare to the spin-valve (SV) devices. These results strongly suggest that the spin transfer torque random access memory based on the MTJs with perpendicularly magnetized free layer will likely have the multiple benefits of much larger intrinsic signal, smaller switching current, and faster switching speed than the SV devices.