Collaborative Research: Engineering, imaging and control of three-dimensional topological magnetic materials

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NON-TECHNICAL SUMMARYWhereas the vast majority of the world’s digital information is processed using nanoscale devices to manipulate the charge of electrons, most of this information is stored using the spins of electrons in the form of nanoscale magnetic domains. Recent advancements in magnetic materials and nano-characterization techniques have revealed nanoscale magnetic knots formed by the spins of many electrons. Topology is a property to describe the different types of magnetic knots, and could enable new types of electronic devices for sensing, processing, and storing information. This Collaborative Research project develops abilities to produce, manipulate, and characterize these knotted magnetic features. The project engages a wide age range of students on meaningful research, including training middle-school-aged summer camp students to use an electron microscope to search for nanoscale “magnetic bow ties”. The project promotes active exchange of students, faculty and researchers between institutions, and both undergraduate and graduate student researchers are educated in a broad range of materials challenges and nanoscale measurement techniques using novel and sophisticated equipment. A key component of the proposal is to foster collaborations between leading international and industrial scientists to provide international research experience for graduate students. This will not only strengthen the scientific excellence and broaden the impact of the research, but it will also provide important educational and post-graduate career opportunities for both graduate and undergraduate students. TECHNICAL SUMMARYNew functionality in nanomagnetic devices requires control of magnetic order at the nanometer spatial scale. Many spin-based devices are still in their infancy and a thorough understanding of the underlying materials and electronic properties and their effect on device performance will be essential for future applications. This Collaborative Research proposal builds on a strong existing collaboration between the PIs Fullerton and McMorran, international and industrial partners, and Harvey Mudd College to achieve a fundamental understanding of and ability to control the topological spin order in nano-structured magnetic materials and devices. The research is particularly interested in the design, manipulation and imaging of thin-film materials that exhibit complex 3-D topological states and defects such as chiral hybrid domain walls, chiral helixes, skyrmions, bi-skyrmions, antiskyrmions and hopfions. The morphology of the domains and defects depends sensitively on the underlying materials properties as well as on the application of magnetic fields, field history, and temperature where domains can arrange in metastable configurations including various topological defects. The team will develop and apply several recent methods in advanced electron microscopy to characterize the structure of these topological states, as well as their behavior under the influence of ultrafast fields. Summer curriculum is developed for the 7-12th grade and undergraduate levels to educate students on the use of nanoscale tools, and engage them in meaningful supervised research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.