Direct Imaging of Magnetic Vortex Motion in Notched Ferromagnetic Nanowires
Abstract
Great interest has been shown in using current to move domain walls in nanowire geometries, particularly due to the view that it presents a novel method to control a variety of spintronic phenomena. Micromagnetic calculations suggest that it is possible to manipulate controllably magnetic vortices pinned by notches in nanowire structures using resonant AC currents, and that resonant behavior varies depending on the chirality of the domain wall. While previous works used electrical measurements in combination with numerical simulations to infer an orbit, we use in-situ, high-resolution Lorentz transmission electron microscopy and a custom sample holder to study the orbits of magnetic vortices pinned by the notches in patterned permalloy nanowires. For the first time, we present direct images of the variations in resonant behavior in such notches for different chiralities. By sweeping the AC frequency through resonance, we are able to measure the gyrational amplitude vs. frequency with unprecedented precision. Through comparisons with micromagnetic calculations, we determine the depth of the local pinning potential for both chiralities.
- Publication:
-
APS March Meeting Abstracts
- Pub Date:
- March 2013
- Bibcode:
- 2013APS..MARA15012P