Continuous film spin–orbit torque characterization via four probe measurement

Spin–orbit torque (SOT) characterization techniques generally require the Hall cross that demands lithography resources and time. It is highly desirable to characterize SOT efficiencies with minimal sample processing Here, we demonstrate a lithography-free technique determine spin–orbit efficiency in perpendicular magnetic anisotropy ferromagnetic heterostructure. By utilizing customized four-point probe rhombus geometry, harmonic measurement was performed on continuous films of Pt/Co/Ti structure efficiency. A correction factor, which due non-uniform current distribution across film, experimentally evaluated by taking ratio measured damping-like field film fabricated device. Additionally, this factor analytically derived shown be determined configuration probes independent material. Our reveals performing single calibration process for particular set probes, same validated second heterostructure, Ti/Pt/Co/Ta; hence, it can applied other films' stack measurements. four-probe provides an alternative swift way investigations eliminating multiple processes necessary conventional approaches.