Giant enhancement of spin-orbit torque by interface scattering from ultra-thin insertion layers

A magnetic device, comprising:

• a magnetic tunneling junction (MTJ) that includes (1) a pinned magnetic layer having a fixed magnetization direction, (2) a free magnetic layer having a changeable magnetization direction, and (3) a non-magnetic junction layer between the free magnetic layer and the pinned magnetic layer and formed of an insulator material sufficiently thin to allow tunneling of electrons between the free magnetic layer and the pinned magnetic layer;
• and
• a spin Hall effect metal layer including a metal exhibiting a large spin Hall effect to react to a charge current directed into the spin Hall effect metal layer to produce a spin-polarized current that is perpendicular to the charge current, and the spin Hall effect metal layer being parallel to and adjacent to the free magnetic layer to direct the spin-polarized current generated in the spin Hall effect metal layer into the free magnetic layer,
• wherein the spin Hall effect metal layer includes one or more insertion metal layers arranged inside the spin Hall effect metal layer and operable to introduce interfacial scattering of electrons flowing in the spin Hall metal layer to increase the spin current that interacts with and changes the magnetization of the free magnetic layer of the MTJ.