Origin and Manipulation of Stable Vortex Ground States in Permalloy Nanotubes

• DOI: 10.1021/acs.nanolett.7b05222
• Publication Date: 2018-04-06T06:07:56Z
• Authors: Michael Zimmermann; Thomas Norbert Ge...; Florian Dirnberger; Attila Kákay; Martin Decker; Sebastian Wintz; Simone Finizio; Elisabeth Josten; Jörg Raabe; Matthias Kronseder; Dominique Bougeard; Jürgen Lindner; Christian Horst Back
• Keywords: Permalloy

We present a detailed study on the static magnetic properties of individual permalloy nanotubes (NTs) with hexagonal cross-sections. Anisotropic magnetoresistance (AMR) measurements and scanning transmission X-ray microscopy (STXM) are used to investigate their ground states its stability. find that magnetization in zero applied field is very stable vortex state. Its origin attributed strong growth-induced anisotropy easy axis perpendicular long tubes. AMR NTs combination micromagnetic simulations allow determination magnitude for different types NT coatings. show strength can be controlled by introducing buffer layer underneath layer. The depend external history directly imaged using STXM. Stable domains introduced fields erased radio-frequency at center tubes via strip line antenna.