Topological Spin Textures at the Surface of Chiral Magnet MnGe
A Pitt Physics seminar
Abstract: Magnetic skyrmions and topological spin textures have been investigated as possible information carriers in next generation devices. Among the well-studied B20 materials, MnGe is an interesting outlier that has been shown to host a novel three-dimensional hedgehog/anti-hedgehog lattice (HL) with a very short period (~3 nm). Here, we use spin-polarized scanning tunneling microscopy (SP-STM) at low-temperature (~5 K) to directly observe the spin textures present at the surface of an 80 nm MnGe thin film. We find the HL is not present, and instead observe a multi-domain spin spiral state characterized by a tilted wavevector and surface periodicity of 6-10 nm. By combining our measurements with micromagnetic modeling, we gain understanding of individual domains and their intersections. We find three domains can meet in two distinct ways to produce either a “target-like” or “ -like” spin texture. Each is associated with a unique topological charge density and are correlated with local strain in the film. We further show the target texture can be reversibly manipulated using current/voltage pulsing with the STM tip or applied magnetic fields, a promising step toward applications.