The influence of interface effects on the switching behavior in ultra-scaled MRAM cells

The development of advanced magnetic tunnel junctions with a single-digit nanometer footprint can be achieved using an elongated multilayered ferromagnetic free layer structure. In this work, we demonstrate the switching of a composite free layer consisting of two ferromagnets separated by an MgO layer and an additional capping MgO layer to boost perpendicular anisotropy. This serially connected MTJs form a multi-state memory cell. Because of the ability to store data in more than one bit (0 or 1), the memory density can be increased, making the memory more efficient and cost-effective. A proper design of the free layer and its interface-induced perpendicular anisotropy helps to achieve reliable switching. •Novel formalism to simultaneously describe spin–charge transport in MTJs and spin valves.•Interface induced anisotropy and effects of short spin dephasing length.•Sequential switching of a composite free layer.•Accelerated switching for the anisotropy localized at the interface compared to bulk.