Direct comparison of domain wall behavior in permalloy nanowires patterned by electron beam lithography and focused ion beam milling

Nominally identical permalloy nanowires, with widths down to 150 nm, were fabricated onto a single-electron transparent Si3 N4 membrane using electron beam lithography (EBL) and focused ion beam (FIB) milling. Transmission electron microscopy (TEM) experiments were performed to compare the nanostructures produced by these two techniques in what we believe is the first direct comparison of fabrication techniques for nominally identical nanowires. Both EBL and FIB methods produced high quality structures with edge roughness being of the order of the mean grain size 5–10 nm observed in the continuous films. However, significant grain growth was observed along the edges of the FIB patterned nanowires. Lorentz TEM in situ imaging was carried out to compare the magnetic behavior of the domain walls in the patterned nanowires with anti-notches present to pin domain walls. The overall process of domain wall pinning and depinning at the anti-notches showed consistent behavior between nanowires fabricated by the tw...