Physics Seminar: Jake Repicky (Ohio State University)
Topological Spin Textures at the Surface of Chiral Magnet MnGe
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.
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