SPIN ORBIT TORQUES AND DZYALOSHINSKII-MORIYA INTERACTION IN MAGNETIC MULTILAYERS

Abstract

Spintronics is an emerging research area focusing on the manipulation of ferromagnet (FM) magnetization by electrical current. Current switches the magnetization by current induced spin-transfer torque (STT) or spin-orbit torque (SOT). One of the fundamental obstacles for high-density NV applications of magnetic devices is the efficiency of the current induced torques. My work mainly focuses on increasing the SOT efficiency to switch the magnetization with a lower current density. To achieve a larger spin torque, various materials have been explored as heavy metal (HM) and recording blocks (FM as well as ferrimagnets). We also carefully study the mechanism of SOT induced switching through domain wall expansion under the influence of Dzyaloshinskii-Moriya Interaction (DMI). With these research works, we could increase the spin torque dramatically as compared with literature reports. Meanwhile, we could obtain satisfactory thermal stability, which is another dragging leg for the SOT-based device applications.