Deep learning for spin-orbit torque characterizations with a projected vector field magnet

Abstract

Spin-orbit torque characterizations on magnetic heterostructures with perpendicular anisotropy are demonstrated on a projected vector field magnet via hysteresis loop shift measurement and harmonic Hall measurement with planar Hall correction. Accurate magnetic field calibration of the vector magnet is realized with the help of deep learning models, which are able to capture the nonlinear behavior between the generated magnetic field and the currents applied to the magnet. The trained models can successfully predict the applied current combinations under the circumstances of magnetic field scans, angle scans, and hysteresis loop shift measurements. The validity of the models is further verified, complemented by the comparison of the spin-orbit torque characterization results obtained from the deep-learning-trained vector magnet system with those obtained from a conventional setup comprised of two separated electromagnets. The damping-like spin-orbit torque (DL-SOT) efficiencies

The central role of tilted anisotropy for field-free spin–orbit torque switching of perpendicular magnetization

“…Electrical measurements on Hall bar devices are performed with a current source (Keithley 2400) and a voltage meter (Keithley 2000) integrated into a probe station with or without electromagnets based on the characterization purpose. The electromagnets are typical homemade coils with iron cores in the case of applying a typical field along the x; y; z-axis and a commercial projected vector field magnet of model GMW Associates Model 5204 for applying arbitrary vector fields based on the previously established framework 35 . An X-ray diffractometer (XRD) (model Rigaku TTRAX-III) was used to characterize the crystallinity of the deposited films.…”

University Technology Commercialization in Taiwan: National Taiwan University (NTU) and National Taiwan University of Science and Technology (NTUST)

“…1(b) depicts (please refer to Ref. [40] for the details of the calibration technique). Representative RH hysteresis loop of a [Pt/Co]n multilayer sample with n = 1 is shown in Fig.…”