Physics Theses and Dissertations

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https://hdl.handle.net/1794/2048

This collection contains some of the theses and dissertations produced by students in the University of Oregon Physics Graduate Program. Paper copies of these and other dissertations and theses are available through the UO Libraries.

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Browsing Physics Theses and Dissertations by Subject "Antiskyrmions"

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    Direct Experimental Observation of 3D Vortex States in Multilayer Fe/Gd using Scanning Electron Microscopy with Polarization Analysis (SEMPA)
    (University of Oregon, 2023-07-06) Moraski, Rich; McMorran, Benjamin
    The global market for power solely for data center usage is estimated to be $12.4 billion by 2027[1]. In 2021, data center electricity consumption was ∼400 TW h, representing almost 2% of the global energy demand[2]. Ongoing efforts in spintronics, which use spin currents instead of traditional charge currents at a fraction of the power[3], are paving the way for significant savings, both financially and environmentally. There has been considerable research into alternatives for memory[4–6] including a magnetic structure known as a skyrmion, a self-supporting magnetic texture characterized by a non-trivial topology. Recent advances in creating room-temperature stable skyrmions has reignited interest in these objects. Building on previous work in the McMorran group, this research set out to build a more complete understanding of the 3D structure of metastable magnetic skyrmions, specifically in Fe/Gd thin films. This was done using traditional trans- mission electron microscope (TEM) techniques along with a unique scanning elec- tron microscope with polarization analysis at the University, the SEMPA. Data col- lected using a TEM in Lorentz mode, providing information integrated through the bulk of the material, was combined with data from SEMPA, providing surface- sensitive information about the top of the material. Analysis of the data suggests atopologically complex winding nature for the magnetization of skyrmions in this material. Presented herein is a brief introduction of the magnetic structures found in Fe/Gd multilayer thin films; an analysis using new analytical tools built for this purpose of the data collected; and a user’s manual for SEMPA, including mainte- nance and troubleshooting guidance.