Physics Colloquium: Nanostructured Materials – From Magneto-Ionics to Fighting COVID-19
Abstract: The energy consumption in information and communications technology already accounts for over 10% of the world’s total electricity usage and continues to rise rapidly. This energy challenge is in part manifested in the coming end of the Moore’s law. The on-going COVID-19 pandemic highlights the severe health risks posed by deep submicron airborne particulates in the spread of infectious diseases, and calls for the development of efficient, durable and reusable filters for this size range. Nanostructured materials offer an exciting platform to address such diverse challenges we face today, as will be illustrated in this talk. For example, magneto-ionics has shown promise for energy-efficient nanoelectronics, where ionic migration can be used to achieve atomic scale control of interfaces in magnetic nanostructures, and in turn modulate a wide variety of functionalities. Recently, we have discovered that chemisorbed oxygen and hydrogen on the surface of ferromagnetic films can induce significant Dzyaloshinskii–Moriya interaction (DMI) , a handle to introduce topology into nanoscale magnets to control chiral domain walls and magnetic skyrmions [2,3]. The ionic motion can be further controlled by an electric field, avoiding the usual Joule heating . These effects are relevant for 3-dimensional information storage, such as interconnected nanowire networks . Interestingly, nanoporous metal foams made of random assemblies of nanowires have found applications in deep-submicron particulate filtration, relevant to combatting COVID-19 and air pollution. Such foams are efficient, breathable, light-weight, robust, and can be reused and recycled . Our mask design based on such foams has been selected by BARDA-NIOSH as a Phase 1 Winner of the Mask Innovation Challenge .
Work supported by NSF, SRC/NIST, KAUST, UCD and GU.
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 BARDA-NIOSH Mask Innovation Challenge.