SPIN-ORBIT TORQUE IN MAGNETIC MULTILAYERS AND ITS DEVICE APPLICATIONS

Abstract

Extensive efforts have been devoted to the study of spin-orbit torque (SOT) in magnetic multilayers and its application in spintronic devices. In this thesis, we firstly present the observation of global ferromagnetic order and large SOT effect in [FeMn/Pt]n multilayers, as well as SOT-based reversible magnetization switching without any thickness constraint and assistant field. Thereafter, we demonstrated a new type of magnetoresistance (MR) sensor ‒ spin Hall magnetoresistance (SMR) sensor, with the SOT effective field as the built-in linearization mechanism, which effectively removes the sophisticated linearization mechanism in commercial MR sensors. By further introducing the AC excitation and rectification detection technique, an all-in-one SMR sensor which embodies multiple functions of AC excitation, domain stabilization, rectification detection, and DC offset cancellation is developed, and importantly, all these features are realized in a simplest possible structure which consists of only a NiFe/Pt bilayer.