Cr-induced Perpendicular Magnetic Anisotropy and Field-Free Spin-Orbit-Torque Switching

Current-induced spin-orbit torque (SOT) driven magnetization switching has relied mostly on 4d and 5d heavy metals with strong spin-orbit coupling to generate large spin currents to deliver SOT and a MgO layer to acquire perpendicular magnetic anisotropy (PMA). We demonstrate 3d Cr metal can generate PMA and deliver SOT switching with more prowess than Ta. In certain Cr-based heterostructures, even field-free SOT switching has been achieved due to the subtle microstructure in the layered structure. The field-free SOT switching device based on 3d Cr provides significant advantages for next generation high-efficiency and low-cost nonvolatile spintronic devices.