Helium Ion Microscopy for Reduced Spin Orbit Torque Switching Currents

Spin Orbit Torque (SOT) is an efficient way to electrically manipulate nanoscale magnetic objects for high-speed, high-density, and low power spintronic devices. However, the higher critical current density, j_c, requirement for the switching of magnetization is one of the major bottlenecks that limit the practical application of SOT in memory devices.  We achieve an order of magnitude reduction in j_c by irradiating magnetic thin films using focused helium ion beams, He⁺. Our key advancement is the ability to monitor in-situ the evolution of the out-of-plane magnetization under local ion irradiation using the anomalous Hall effect. This tool combination allows both precise control of the anisotropy and <2 nm spatial resolution, all while avoiding additional lithography steps needed for patterned broad beam irradiation. We demonstrate a promising and practical approach for the reduced power consumption in SOT-based spintronic devices which opens the door to preferential current driven magnetization switching of predetermined areas of the sample, limited by the resolution of the ion beam microscopy.