Magneto-Ionics and 3D Nanowire Networks
Wednesday, September 28, 2022 1:30pm to 2:30pm
About this Event
Registration: https://harvard.zoom.us/webinar/register/WN_q8rI_YJWS2GiLNyxVADNKA
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) [1], a handle to introduce topology into nanoscale magnets. This has enabled direct tailoring of skyrmions winding number as well as wall type at room temperature via oxygen chemisorption. We have also demonstrated a sensitive and reversible chirality switching of magnetic domain walls [2] and writing/deleting of skyrmions [3] via hydrogen chemisorption/desorption [3] or changing the thickness of a sub-monolayer Pd capping layer [4]. These effects offer an ideal platform to gain quantitative understanding of magneto-ionics at buried interfaces, where the ionic motion can be further controlled by an electric field [5]. They are relevant for 3-dimensional information storage as a potentially contactless way to address spin textures, such as in interconnected nanowire networks [6]. 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 [7].
Work supported by NSF, SRC/NIST, KAUST, UCD and GU.
[1] Science Advances, 6, eaba4924 (2020).
[2] Physical Review X, 11, 021015 (2021).
[3] Nature Communications, 13, 1350 (2022).
[4] Nano Letters, 22, 6678 (2022).
[5] ACS Applied Materials and Interfaces, 13, 38916 (2021).
[6] Nano Letters, 21, 716 (2021).
[7] Nano Letters, 21, 2968 (2021).