Third type of domain wall in soft magnetic nanostrips
Résumé
Magnetic domain walls (DWs) in nanostructures are low-dimensional objects
that separate regions with uniform magnetisation. Since they can have dierent
shapes and widths, DWs are an exciting playground for fundamental research,
and became in the past years the subject of intense works, mainly focused on
controlling, manipulating, and moving their internal magnetic conguration. In
nanostrips with in-plane magnetisation, two DWs have been identied: in thin
and narrow strips, transverse walls are energetically favored, while in thicker and
wider strips vortex walls have lower energy. The associated phase diagram is now
well established and often used to predict the low-energy magnetic conguration
in a given magnetic nanostructure. However, besides the transverse and vortex
walls, we nd numerically that another type of wall exists in permalloy nanos-
trips. This third type of DWis characterised by a three-dimensional,
ux closure
micromagnetic structure with an unusual length and three internal degrees of
freedom. Magnetic imaging on lithographically-patterned permalloy nanostrips
conrms these predictions and shows that these DWs can be moved with an
external magnetic eld of about 1 mT. An extended phase diagram describing
the regions of stability of all known types of DWs in permalloy nanostrips is
provided.
Origine : Fichiers produits par l'(les) auteur(s)
Origine : Fichiers produits par l'(les) auteur(s)