Beam-induced Fe nanopillars as tunable domain-wall pinning sites

Abstract

Focused-electron-beam-induced deposition (FEBID) is employed to create freestanding magnetic nanostructures. By growing Fe nanopillars on top of a perpendicular magnetic domain wall (DW) conduit, pinning of the DWs is observed due to the stray fields emanating from the nanopillar. Furthermore, a different DW pinning behavior is observed between the up and down magnetic states of the pillar, allowing to deduce the switching fields of the pillar in a novel way. The implications of these results are two-fold: not only can 3-dimensional nano-objects be used to control DW motion in applications, it is also proposed that DW motion is a unique tool to probe the magnetic properties of nano-objects. Vertical magnetic nanopillars grown by electron-beam induced deposition are used to control pinning of magnetic domain walls, moving through an underlying conduit. The pinning strength depends on the height and magnetic state of the pillars, and this is used to determine the switching field of the pillars themselves. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.