title: Magnetic microscopy and topological stability of homochiral Néel domain walls in a Pt/Co/AlOx trilayer.
abstract: The microscopic magnetization variation in magnetic domain walls in thin films is a crucial property when considering the torques driving their dynamic behaviour. For films possessing out-of-plane anisotropy normally the presence of Néel walls is not favoured due to magnetostatic considerations. However, they have the right structure to respond to the torques exerted by the spin Hall effect. Their existence is an indicator of the interfacial Dzyaloshinskii-Moriya interaction (DMI). Here we present direct imaging of Néel domain walls with a fixed chirality in device-ready Pt/Co/AlOx films using Lorentz transmission electron and Kerr microscopies. It is shown that any independently nucleated pair of walls in our films form winding pairs when they meet that are difficult to annihilate with field, confirming that they all possess the same topological winding number. The latter is enforced by the DMI. The field required to annihilate these winding wall pairs is used to give a measure of the DMI strength. Such domain walls, which are robust against collisions with each other, are good candidates for dense data storage.
authors.affiliation: School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland.
authors.forename: M J
authors.initials: MJ
authors.lastname: Benitez
authors.affiliation: School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: A
authors.initials: A
authors.lastname: Hrabec
authors.affiliation: School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: A P
authors.initials: AP
authors.lastname: Mihai
authors.affiliation: School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: T A
authors.initials: TA
authors.lastname: Moore
authors.affiliation: School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: G
authors.initials: G
authors.lastname: Burnell
authors.affiliation: School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland.
authors.forename: D
authors.initials: D
authors.lastname: McGrouther
authors.affiliation: School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: C H
authors.initials: CH
authors.lastname: Marrows
authors.affiliation: School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland.
authors.forename: S
authors.initials: S
authors.lastname: McVitie