Ultrahigh-Density Arrays of Ferromagnetic Nanorings on Macroscopic Areas


  • This research is financially supported by NSF and DARPA.


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Arrays of ten billion Co nanorings, with inner diameters of 100 nm, wall widths of 20 nm, and of an ultrahigh areal density of 45 rings μm–2, are fabricated on a macroscopic area. Magnetometric measurements and micromagnetic simulations reveal two parallel switching processes: a vortex reversal process and a rotating onion process.