Non-collinear magnetism studied with spin-polarized scanning tunneling microscopy

Abstract

Non-collinear magnetic states in nanostructures and ultra thin films have moved into the focus of research upon the experimental discovery that the interface -induced Dzyaloshinskii–Moriya interaction (DMI) can play a crucial role for the magnetic ground state. In particular, DMI-induced magnetic skyrmions, which are particle-like knots in the magnetization of two-dimensional systems, have attracted significant attention due to their potential use in future spintronic devices. Since then, research has focused both on tailoring thin-films and multilayers hosting magnetic skyrmions, and investigating specific processes such as controlled lateral movement, detection, as well as writing and deleting of single magnetic skyrmions. This chapter reviews the fundamental interactions and mechanisms for the formation of non-collinear spin textures and then introduces how scanning tunneling microscopy (STM) can be exploited to investigate such magnetic states. Next, examples of (one-dimensional) spin spirals will be discussed before the emergence of two-dimensional non-collinear spin textures is studied and characterized in detail. Finally, different mechanisms for the controlled writing and deleting of magnetic skyrmions with the STM tip are explored.