Robust magnetic field-free switching of a perpendicularly magnetized free layer for SOT-MRAM

We investigate the robustness of a purely electrical field-free switching of a perpendicularly magnetized free layer based on SOT. The effective magnetic field which leads to deterministic switching of a rectangular as well as of a square free layer is created dynamically by a two-current pulse scheme. It is demonstrated that the switching is very robust, being insensitive to fluctuations of the write pulses' durations and to relatively large variations of the heavy metal wires' dimensions. Furthermore, it remains reliable for a wide range of synchronization failures between the pulses. The combination of a rectangular free layer shape with a partial overlap with the second current line accelerates the switching of the cell allowing a fast, 0.25 ns, switching.